Not An Audiophile – The Podcast featuring Jon De Sensi founder of OAD Ultrafidelity, the company that has set new standards in the audio industry. Their flagship products, the Padma preamplifier and the Vajra power amplifier, are a testament to John’s commitment to excellence. These products are not just about delivering high-quality sound; they are a blend of meticulous design, superior craftsmanship, and cutting-edge technology.
Podcast transcripts below – Episode 005
TRANSCRIPT
SEASON 1 – EPISODE 005 – Jon De Sensi, OAD Ultrafidelity, Australian Made & fully CNC routed chassis
Andrew says the weather in Melbourne is surprisingly warm this time of year
Andrew Hutchison: And you were saying before we came on air that the weather in Melbourne is actually surprisingly warm for this time of the year.
Jon De Sensi: I wouldn’t say warm, but it’s surprisingly good.
Andrew Hutchison: Andrew here from Not An Audiophile. Thank you for listening. Today is episode five, season one. And we have Jon De Sensi from Melbourne, from OAD Ultrafidelity on the line and Brad Serhan in Sydney, from Serhan and Swift. Jon’s a very interesting guy, and a very smart fellow. beautiful, amplifier, preamplifier and power amp combination. a beauty to behold and sounds delightful as well.
Andrew: Jon, you have an amazing audio product. The fit and the finish, the design
So without any further ado, I have met you briefly, Jon, once, at a show, you showed me the pre power amplifiers which you’re going to pronounce the names of shortly. And I was staggered, I think is the word, with the.
Jon De Sensi: Oh, really?
Andrew Hutchison: Well, absolutely. The fit and the finish, the design, the industrial design, it’s an absolutely world class product. And certainly one of the key reasons I wanted to have you on the podcast was just to discuss how the hell you could make that happen because my understanding is that you make the vast majority of the product, in this. Well, you make it in this country, but you use predominantly locally made, you know, sub assemblies and parts and what have you. So, and Brad, I know, wants to talk about the more technical side of it, the nuts and bolts of your transistor selections, apparently. So we’ll get, we’ll get to that.
Brad Serhan: I have very limited knowledge in that area, Andrew. I’m going to leave it to you and Jon to discuss that.
Andrew Hutchison: But anyway, well, we’re not going to. Let’s not, turn it into too much of an electrical engineering discussion. But I guess from a potential bias perspective. I mean, there’s a key thing, and that is that it’s made in this country. You designed it, we believe. And I’d like you to tell us how that even got. How did it happen and how did you get started? In two sentences, where you go now. Take us. Take as long as you like.
Jon De Sensi: Well, we did make some more humble, chassis which are also on the website under the discontinued equipment, menu. and people really loved the sound, but they thought that the appearance didn’t really quite match the sound. The appearance is, you know, a bit like your sort of, you know, eighties, nineties audio research, you know, nice CNC front panel.
Andrew Hutchison: Yeah.
Jon De Sensi: and then sort of folded metal chassis, and during, during COVID I had a lot of time, on my hands and a customer of mine, or someone who became a customer of mine, contacted, me and said, I’m a shithot, CNC machinist. I can’t afford your equipment, but I can design you a really nice remote control. and maybe we could do a bit of a barter. And eventually, we redesigned the preamp and the power amp. Now, the preamp is called the Padma, and the power amp is called the Vajra.
Andrew Hutchison: Okay.
Jon De Sensi: And there’s a little bit of a story behind those two.
Andrew Hutchison: Yeah, well, yeah, the spelling is, pretty much as it sounds, actually. So m not as complicated as I thought. so, interesting. So that’s to some degree, you sort of fell on your feet a little bit with that incredibly high level of CNC. Finished. is that right? Because the guy rang you?
Jon De Sensi: Yeah, yeah. Well, actually, he emailed me.
Andrew Hutchison: Okay.
Jon De Sensi: And I just ignored it because I get a lot of. Because I. I get a lot of them, or not a lot, but I get a few emails.
Andrew Hutchison: Yeah.
Jon De Sensi: People just want things, but nothing. Or they want things, you know, on the cheap. And I just thought he was just another nutter. And then, I did the Melbourne audio show in 2017, I think.
Andrew Hutchison: Yeah. Okay.
Jon De Sensi: Yeah. And, I met him, and we just hit it off from the very first minute. and then it turned out that we’re actually eight minutes away from each other’s houses.
Andrew Hutchison: Okay.
Jon De Sensi: and we’ve become the best of friends. We probably are the best friends of each other. And,
Andrew Hutchison: Wow.
Jon De Sensi: You know, we’re constantly at each other’s houses every week. Okay.
Andrew Hutchison: Yeah, well, that’s a. That’s an amazing story. Okay. So that.
Jon De Sensi: Well, I guess that was meant to be.
Andrew Hutchison: It was meant to be. And it goes some way, I guess, to explaining just how the finish ends up as good as it is.
00:05:00
Andrew Hutchison: And for those that are, maybe listening and not sure what we’re talking about, it’s OAD Ultrafidelity. And I guess the, web address is literally that with a.com and a dot au on the end of it.
Jon De Sensi: Just.com.
Andrew Hutchison: Just.Com. Okay.
Jon De Sensi: Yeah.
Andrew Hutchison: Huge international company that, Yeah, too big for au. And, Yeah, I mean, it’s. It’s so, Yeah, OAD Ultrafidelity, uh.com. and, I would have a look while you’re listening at the podcast. And you will see, what I’m referring to. Although to see it in the flesh is the go.
So, Melbourne audio show this year on in a few weeks
So I’ll cut a to the chase before I forget. So, Melbourne audio show this year on in a few weeks. Although by the time this episode gets up on in two weeks, maybe it takes a week for or so for us to, edit and, uplOAD it. So, Melbourne HiFi show any minute. early to mid October, I think maybe it starts on the 11th or something. And you’re going to be there. I hope you’re going to say yes.
Jon De Sensi: Yes. Yes, we will be there.
Andrew Hutchison: Excellent. Okay.
Jon De Sensi: And this time we won’t have, our own dedicated room. so Nick Hulgich, who, will hopefully be on your podcast before too long, has been begging me for years about doing a show together. So, we’re sharing a room. And I won’t have my open baffle speakers, particular show.
Andrew Hutchison: But you clearly have his speakers, which are, of course, excellent.
Jon De Sensi: They are.
Andrew Hutchison: They are.
Jon De Sensi: And we’ve done a trial run just a couple of weeks ago. And I’m excited about sharing the room.
Andrew Hutchison: I was going to say, having heard his speakers, maybe at the same show last year, as you were at where I first discovered your amplifiers, because I think you were like almost diagonally opposite.
Jon De Sensi: we were.
Andrew Hutchison: Yeah. Yeah. There was some reason why I just went, well, I could see something through the door there. I’m going to go and have a look at that. And, Yeah, so I spoke to Nick and heard the loudspeakers and I’m going to forget which model, but I tell you what, I scuttled back to my own room to make a quick comparison and was glad that our loudspeaker was a little less expensive because, his R&D. Ah, very, very good. And of course, stunningly well finished. And, I know that he goes to some considerable trouble, well, with all aspects of the design, but, yeah, my memory, my aural memory of the, of the balance of his loudspeaker. And I’m honestly forgotten which amplifier he had it on or what amp. But I tell you what, I reckon your two might, work well together. And that’s what you’ve found so far, is it, Jon?
Jon De Sensi: That, that’s correct. That’s correct. so yeah, we did a trial run. We’re also sharing the room with, Stavros DAC man, who imports, a lot of chinese made equipment, which is very good. And, we got together.
Andrew Hutchison: This show is all about australian made stuff. So that’s actually the wrong thing to say. So if we could just.
Jon De Sensi: Rewind. Rewind.
Andrew Hutchison: Keep rolling.
Jon: Three of us in the room. Um, yes, there’ll be three of us
Okay, so you. So there’s three of you. Three of you in the room.
Jon De Sensi: yes, there’ll be three of us in the room. Yeah.
Andrew Hutchison: Well, you have lots of stuff to.
Jon De Sensi: Look predominantly right up. You know, right up like in people’s faces will be Nick’s beautiful speakers. Which, You know, he’s modified since last year. And they sound even better.
Andrew Hutchison: Okay.
Jon De Sensi: and they work better in the room. And, my amps, which are identical to what was at the show last year.
Andrew Hutchison: Yeah. Yeah. Well, yes. And I. Which room? While we’re on the subject of the. I think it’s called the australian HiFi show. I think that’s the correct title.
Brad Serhan: is it Stereonet.
Jon De Sensi: Stereonet Australia.
Andrew Hutchison: It’s quite a title. so in the pullman hotel. well, in Albert park, across the rOAD from the lake. not hard to find. I think everyone who’s listening who lives in Australia will certainly know where that show is. It’s been in the same location for some years. what room are you in, Jon?
Jon De Sensi: we’re in room 2313.
Andrew Hutchison: 2313. Okay. Yeah, we’ve got that covered. Now.
How far back does your interest in amplifiers go and how did it start
how electronically you. Obviously your knowledge is extremely high. But how far back does it go and how did you end up designing amplifiers?
Jon De Sensi: it’s a bit of a long story. kind of the genesis kind of began in the seventies. When my father. He was a great music lover, from Europe. Who loved his classical music. And, Opera. Italian opera. bought a, Pretty flash at the time. Sanyo four channel, stereo system. Like a big cabinet with the turntable and a receiver. And space underneath from. Remember from what I remember. And then four speakers. So it was actually a quadrifonic, system.
Andrew Hutchison: So this was 1973 or 1974, which is.
Jon De Sensi: Yeah, 1974, I think. And,
Andrew Hutchison: Big year for quad. Quads.
00:10:00
Andrew Hutchison: Surround sound or whatever we should call it. Not quad, as in electrostatics and what have you. But, Yeah, quad. The The thing, not the brand. Yeah, I mean, it was almost like dark side of the moon or something. Was the quad album or something like that. I mean, well, you hit the nail.
Jon De Sensi: Right on the head. Because I was just going to say my brother bought home, a cd, four or four channel version of it. And we popped it on the sanyo turntable. And we were just completely gobsmacked at the time. And yeah, and I’d already had an interest in electronics. But, you know, it became greater and greater from that point onwards. And, you know, I couldn’t afford, obviously, my own system. But I occasionally, Friends of mine had bought japanese equipment. Nice. Ah, sort of onkyo or sansui two of the better brands back then. And I’d sort of, you know, buy the service manuals and we’d go through the service manuals. Okay, this is as a twelve year old. Yeah. Is that a fact? Wow.
Andrew Hutchison: Okay, so that’s right. So you get the manual, as we say in the trade, we just call it a manual. you get the service manual and you, yeah, I mean the circuit was probably all on one flip out page or something at that point. And sometimes they even fold it out, you know, to four sheets worth. So you would have just loved that. I guess you would have just been examining that in its finest detail and I guess trying to understand what each part of the circuit was, what its function was. Is that the case?
Jon De Sensi: That is exactly correct. And I had a bit of an ace up my sleeve because one of my primary school teachers was a fully fledged electronic engineer. wow. Had actually worked for the prestigious telecom labs and had written lots of papers that ended up in . I didn’t know this at the time, of course, but he also lived just around the corner and that’s where my electronics interest, sort of developed. And we were developing more sort of cheeky little sort of mini, kind of CB radio. So we could actually talk privately amongst, our friends at school.
Brad Serhan: I love it.
Jon De Sensi: because we, you know, because we used to get told off about being on the telephone for hours, of course. So we built these little, five watt transmitters.
Andrew Hutchison: Wow.
Jon De Sensi: On the, on the shortwave band. So we’d buy shortwave radios and we tune in.
Andrew Hutchison: Yeah.
Jon De Sensi: to each, each other’s frequency and have a bit of a. Yeah.
Andrew Hutchison: So you sort of like you’d have a Well it’s better than it. So you, you saw duplex frequencies or something or what? Were you transmitting on your other listings? Yeah. Okay, so everyone’s listening to.
Jon De Sensi: So we’d actually have, yeah, we’d have to have our conversation.
Andrew Hutchison: Yep.
Jon De Sensi: And then, turn off the transmitter and then turn on the shortwave radio so we can actually listen to the other person. Have a go. And then I feel like we’ve got.
Brad Serhan: A great big convoy going on, actually. Yeah, I roger that, good buddy.
Andrew Hutchison: Yeah. That’s that’s amazing.
Brad Serhan: Fantastic.
Radio inspector used to drive around looking for illegal transmissions
Jon De Sensi: So where, so what’s illegal, of course?
Andrew Hutchison: Oh, yeah. Highly illegal. And in those days, of course, as you could confirm, I guess, I’m guessing Melbourne was the same as up here. But, But yeah, the radio inspector, you know, used to drive around with about twelve antennas on his car looking, you know, listening for illegal transmissions. I mean, sort of like a high tech version of a parking inspector, I suppose.
Jon De Sensi: And yes, exactly. Exactly.
Andrew Hutchison: So, you didn’t ever get pulled up by him though?
Jon De Sensi: No, no, no, we didn’t, we didn’t. Luckily, you know.
Andrew Hutchison: You know what’s hilarious is that there’s no such thing today as the radio inspector, I’m going to guess. I mean, you could literally start your own radio station and it seems like you’d for a while, get away with it. Is that maybe not true?
Jon De Sensi: But, I think, I think that is true. And unless I, mean, there probably is someone, but they probably sit in an office all by themselves because they have no friends.
Brad Serhan: Well, I was just, I’ve just looked it up, gentlemen, and I just looked up. I love the fact it’s ham radio, which sort of. What a great name. I want to know the derivation of ham radio. But you must be qualified to operate an amateur radio and, operate under a license.
Andrew Hutchison: There are also equipment, yeah, on an amateur band. But what about if you just go, oh, because you can buy, I’m sure you can buy transceivers that cover just about every frequency up to, I don’t know, into the gigahertz, I think. And you can you can just open, a microphone or plug in a signal and you know, I mean, obviously you’d do it on the FM band for, so people could listen in, I guess. But, I don’t think anyone cares because everything’s on the Internet, so. Including FM radio.
Brad Serhan: True.
Jon De Sensi: Yeah, I think, I think if there’s a bit of splatter on,
00:15:00
Jon De Sensi: someone’s television or radio, then, then, you know, if they’re, you know, smart enough to contact the local authorities, you might get busted. But the chances of that are very, like you said, because of so much, streaming, and listening on radio and mobile devices, I’d say your chances are, you know, pretty, pretty small.
Andrew Hutchison: Well, yeah, that’s another angle, isn’t it? That people forget that there’s so much transmission anyhow. Yeah.
got a start in electronics designing things from scratch in high school
So look, so harking back to the local, radio net or whatever you might have called it, so that’s where you clearly got a start in electronics was, or designing things from scratch. Or this transmitter that you, it was some sort of standard, circuit out of, I don’t know, electronics Australia or some UK or american equivalent of that. Is that, is that how that worked?
Jon De Sensi: well, actually it was a design from our science teacher who, of course it was. You know who was the electronic engineer who lived around the corner.
Andrew Hutchison: Oh, wow. Yeah.
Brad Serhan: Proximity effect.
Jon De Sensi: I love it. Yeah, he resigned. He resigned from telecom labs because his mother was sick. So he, needed to be a bit more local. So we were the beneficiary of having this in. A highly intelligent, articulate person, who actually spent his lunch times, teaching us electronics. Because that wasn’t a standard, subject back in primary school and high school. Or high school, actually.
Brad Serhan: Yeah.
Andrew Hutchison: M so it’s a bit of a coup, isn’t it, really? And.
Brad Serhan: Absolutely.
Andrew Hutchison: And that set you on that. I mean, there’s many things that set you on the path, I guess, towards electronic engineering, but that’s, I mean, gee, you sort of lucked in there, didn’t you?
Jon De Sensi: Yeah. Yeah, it was absolutely, I can’t believe my luck because I had no interest in just about anything at the time. And that was the only thing that kind of. I, became very curious about, and it’s, it’s become a lifelong, addiction loving relationship. An addiction. Yeah. Yeah.
Andrew Hutchison: Well, the kind of is, and I’m not quite sure why, but I guess it’s a certain, personality type of something is attracted to the, the mysteries of electronics. The things that you can’t see, but you can make things happen with it. So what, So how, how did things advance from there? So you, this was early high school or years?
Jon De Sensi: Yeah, yeah, I was still at high school, yep.
Andrew Hutchison: And you sort, of, well, at some point you finished high school. And I, mean, I once had an interest in, radio, but, it disappeared at about the age where, I discovered other things were more interesting. So you, continued on your interest in radio or did you quickly move sideways into audio or did you just, just basically chase ladies? What was your,
Jon De Sensi: No, I wish I was chasing ladies, but I didn’t have the, the foresight at the time. and my tunnel vision, kept me in electronics. No, we did move sideways into audio because, as fortune would have it as well. one of my best friends at school who was part of this group of illegal radio transmitters at the time, his father actually, was, was an electronics serviceman.
Andrew Hutchison: Okay.
Jon De Sensi: And he would service, you know, tvs and, you know, almost anything.
Andrew Hutchison: Yeah.
Jon De Sensi: And, so we, you know, we started like getting discarded, you know, japanese amplifiers and then, okay, like I said, ordering service manuals and then going through them and then modifying them and making them, you know, like, you know, sort of bringing them up to sort of what was then being put out by the Americans and the Europeans in high end audio that sort of grade.
Andrew Hutchison: Okay. So I think people who have an interest specifically in better audio equipment would wander in the seventies because this is the late seventies or very early eighties at this point.
Jon De Sensi: Yeah, yeah. Late seventies.
Andrew Hutchison: Late seventies. So what. What kind of modifications or is that something you’ve long forgotten about?
Jon De Sensi: I probably don’t recall all of them, but the main, the main ones I can recall is we. Well, all japanese equipment even today, always include an input m capacitor. So, you know, because they’re worried about DC coming in.
Andrew Hutchison: Sure.
Jon De Sensi: so we eliminated that. and then there’d be a little bit of potentially a little bit of drift, and DC at the output. So we would then insert resistors or a potentiometer actually, in the emitters of the input stage and trim out the DC. Later on we got a bit clever and we started putting in what’s called DC servo loops which kind of automatically tune out the DC or zero at the DC from the output.
Andrew Hutchison: Yeah.
Jon De Sensi: we replaced every type of capacitor, to a polypropylene, if we, if we could.
Andrew Hutchison: Or
Jon De Sensi: A high grade electrolytic. Yep, audio
00:20:00
Jon De Sensi: grade electrolytic. and So that was pretty much it at the time.
Andrew Hutchison: Yeah. So that yet again, the capacitors, you know, copper hiding poor old capacitors. You wouldn’t want to be one, would you? I mean they’re constantly either failing or being told they’re useless.
Jon De Sensi: So
Andrew Hutchison: So what, these are not necessarily just electrolytic capacitors in the signal path though because there’d be really not many of those, I guess. So you, what other parts of the circuit do you feel the electric, the poor old, you know, the much hated electrolytic let the side down?
Jon De Sensi: yeah, well like I said, there was always the one electrolytic, bypassed if it was a good, a really good japanese ant with a ah, you know, a polyester or something.
Andrew Hutchison: Yeah.
Jon De Sensi: in the input so that would get completely removed, and made DC coupled. and then there were the isolatorlytic, you know, on the power supply rails as we call it. And you know, the plus and minus rails. And then of course the big ones are the big electrolytic capacitors in the power supply partly because the Japanese tend to tend to, you know, undersize them. And I You know, and if you. If you do, I realize this later but you know, when I actually got my degree, that if you do an AC model of an audio amplifier, actually the power supply capacitors are actually in the signal path. if you’re just looking at it on a schematic and looking at it you know, from just a signal point of view in DC rails, it’s not that obvious. But actually the capacitor, literally the capacitors in a linear power supply are actually in the signal path. If you do complete AC analysis which is actually what you’re hearing, you know, you’re hearing AC going through the amp because. So that makes a big difference because.
Andrew Hutchison: They’Re not regulated as such.
Orlando got a degree in electronic engineering post university
Is that the.
Jon De Sensi: Yeah, that’s right. They’re not regulated. Yeah, exactly. Yeah. Yeah.
Andrew Hutchison: So that, okay so that’s interesting. Yeah. I’m not sure I’ve heard it presented that way before but that makes, that makes complete sense. Okay. So Very interesting stuff. So I guess we could, we could, we don’t want to skip over the, you know, the 20 odd years that might have occurred between flipping open Sansui integrated amp manuals and working out modifications. and then we don’t necessarily want to jump forward to today, Orlando. But at some point, or maybe what I’m trying to say is how long has OAD been operational for and what happened between the start of that company and I mean in other words what were you doing for a buck post university? You implied you got a degree. A degree in some kind of engineering I’m guessing.
Jon De Sensi: Yeah. Yeah. So we got a degree in electronic engineering.
Andrew Hutchison: Yeah.
Jon De Sensi: And pretty much right at the end of fourth year, there was a whole lot of jobs that opened up in For Department of Defense, a little section called the engineering development establishment. Ede at the time. Yeah, this is back in 1980, 88 I think.
Andrew Hutchison: Okay.
Jon De Sensi: And So I jumped into that position and got my start in designing manpack radios actually for the army. So we had a big, department of Defence had a big contract. Contract with a now non existent company from the UK called Plessy.
Andrew Hutchison: Oh yeah.
Jon De Sensi: And they’d won the contract and it was, I think the project was called Project Raven and they had a, you know they were designing Manpack radio. So whilst they did a lot of design, we did some of the design here in Australia.
Andrew Hutchison: Okay.
Jon De Sensi: And I was brought into that team and And we kind of completed that after a few years. I sort of came in the middle of it. So I’ve got a couple of fun, fun bits to design and and I, yeah, and then after a couple of years I I decided that I didn’t really want to, want to work in the defence industry. So I left and went backpacking overseas for a couple of years and then upon my return I joined the Bureau of Meteorology, as a radar.
Andrew Hutchison: Okay, so not as the storyteller that makes up the fantasies about what the weather’s going to do. Okay.
Jon De Sensi: No, my legs weren’t good enough to be on television. Call out the weather.
Brad Serhan: That’s a shame.
Andrew Hutchison: Well, back then I think I always.
Brad Serhan: Thought you had lovely legs, actually, just.
Jon De Sensi: A little bit on the hairy side.
Andrew Hutchison: I think in those days, they didn’t really do the live cross to the bomb like they do now, where they seem to have a brOAD selection of different people that like to speak on air. But back then it was more, it was,
00:25:00
Andrew Hutchison: you know, they just put out a forecast and it was sucked up by the radio and tv stations and newspapers that never, you never really knew where that forecast came from. It’s only in the last 15 or 20 years, I think the bombers come out of its shell, so to speak. in that time, though, they don’t seem to really gotten any more accurate. But anyhow, that’s another story.
At the Bureau of Meteorology, you were fixing radars
so you actually stuck with Rf there for a while working with plessy radios, which I think every taxi in Australia had one in it in those days. Or was it, a.
Jon De Sensi: Yes, there was a lot of taxis and, and police and ambulance fire services, I would imagine.
Andrew Hutchison: Yeah, it was, it was a big brand of two way radio and.
Jon De Sensi: They had Motorola, I think was one of the main suppliers. From memory.
Andrew Hutchison: Yeah. Okay. Oh yeah, yeah. Well you know, I mean I certainly saw them but yeah, I never got involved with fixing radios. Strictly audio, audio all the way. so you decided at some point to, well, you got out of the defense forces, you’re involved with the bomb. But I got a feeling there’s, other than a background music system, there’s not a lot of audio equipment requirement, at the Bureau of Meteorology, you were fixing radars. So even higher frequencies, I guess. I mean what frequency did radar, does radar or did radar operate on in those days?
Jon De Sensi: well they still operate on the same frequencies. So, most countries and including Australia, we have two, there are two bands, one’s called c band and one’s called s bandhead and c band is around the 5 GHz. Wow.
Andrew Hutchison: she said he’s high.
Jon De Sensi: yeah. And well, the reason why we have two different frequencies, I think the s band was around just above mobile phones. I think that’s sort of 1.5 gigs. and the reason being is because of the different wavelengths. actually we’ll pick up different size sort of ice particles in clouds. So one can be better than the other depending on what’s in the clouds at the time. So we tend to have two types of radar systems. and that’s roughly about the time that I met Brad for the very first time. Because on the side, I don’t want.
Andrew Hutchison: To cut you off, but I will. so I feel like Brad turned up at the bureau of Meteorology with a frozen chook. And he asked if he could sit it in front of one of the m radars.
Brad Serhan: Ah, no, Andrew, you got it wrong. It was the golden goose.
Andrew Hutchison: And I’m just wondering at 5 mean, what, what are microwaves like? As in what, what’s a magnetron put out? Is it, is there any way you can cook meat with a radar? Is what I’m saying.
Jon De Sensi: no, certainly you can. Certainly. I don’t think the power was, you know, quite. I mean it was a pulse, of course. And the power, you know, because of the duration, there probably wasn’t enough power to cook you. but having said that, we did have annually, we’d have Check medical. Yeah, checkups. Because we were working with these radars all the time and it could have made us sterile and all sorts of things that we’d actually have to have. I can’t actually remember how the tests actually went, but I know we did them every year. Blimey.
Andrew Hutchison: You’re like told to, you know, put your hand in front of him. Anything that you’re particularly attached to while working near a radar. because that’s, that was the workplace health and safety standards we had, I think, at the time, wasn’t it?
Brad Serhan: They provide you with a cricketing box or something like that.
Jon De Sensi: yeah, we needed a cricketing protector cage protocol.
Brad Serhan: And in your case, Jon, I won’t go into size, but yeah, I understood.
Jon De Sensi: Maybe that’s why I didn’t get one.
Brad Serhan: How obvious of me. that’s right. You didn’t need one.
Jon De Sensi: Okay.
What was the storm event that created that catalyst for us meeting
Brad Serhan: so what was the storm event that created that catalyst for us meeting? You know, pardon the obvious part.
Jon De Sensi: Sorry. You know, it’s a good question because I try to think about it and I can’t remember the exact details, but it was I think it was, over in Sydney and I on the side, I’d started another. Started a company thinking, that that would be my way out of, working for anybody else called, music labs.
Brad Serhan: I, ah, remember it well, Jon. I remember that part well, exceptionally well.
Jon De Sensi: And our very first product came out in 1990, which was probably at the time a world class, d two, a converter, using Burr brown 20 bit, ladder dacs, which were the bee’s knees at the time. we’d also used, the best digital filter that came out of Japan, company called NGC. And we did some. Did some funny or not some funny, but we did some advanced things that people didn’t do at the time. We, had really good anti jitter circuitry.
Brad Serhan: She’s ahead of your time.
Jon De Sensi: Yeah, yeah, it was pretty. We just didn’t use a crystal, which is what all the, dacs that came out at the time were using. We actually developed our own, sort of pll. circuit and got the jitter right down. Not that it’s as critical as it is now with the, sigma delta dacs, run at much higher clock frequencies and far more susceptible to jitter, issues. and we also did something that I’ve never seen before or since, and that is that, the I two s. I’m m sorry to get a bit technical, the four data line or the four signals that need to go from the digital filter to the dax. we actually opto coupled. So there was actually no electrical connection between all of the digital stuff that came in, you know, the spdif and, and the digital filter, and the analog output circuitry. So, that was really just reduced the noise floor and any digital noise, just completely eliminated.
Brad Serhan: just to show my, two bobs working. We heard that. I’m not sure when we left the music, lapse with us, I think with Ketnight Orpheus. And it was gobsmackingly good. Just a. Yeah, it was amazing. An amazing, amazing dag.
Jon De Sensi: Yeah. And beautiful sounding. Yeah. And God bless, the great Peter Stein from me sound. But he, Yes, he liked it so much and re badged it for a while.
Andrew Hutchison: Oh, is that right?
Jon De Sensi: Sold it under the me brand, which is, I think, how we all got together in Sydney.
Brad Serhan: I think so, too. Yeah, you’re right.
Jon De Sensi: Peter Stein, you know, he introduced me to you, Brad, and your lovely Orpheus speakers at the time. Yeah. and. And then there was me. Like, I don’t know if there was anyone else. But I just. Yeah, I can’t remember. Remember it all that well.
Andrew Hutchison: Yeah. Now. The drugs.
Brad Serhan: Peter Stein was a gem.
Jon De Sensi: Yeah. Yeah. Yeah. Ah, absolutely. Well actually sad.
Andrew Hutchison: It’s Yeah, I mean he’s no longer with us. Well, yeah. And He. He’s. He was a super smart cookie. Nearly as. Probably as smart as yourself, Jon. And He And I’m being slightly facetious. I have no idea who’s the smartest.
Jon De Sensi: I think is a bit smarter.
Andrew Hutchison: Well, he did sell a hell of a lot of amplifiers. But the biggest difference between. And this is not being. This is not being unkind towards Peter because The thing is, manufacturing has moved on, of course. Processes and I capabilities and what have you. He was building amps at a time when CNC was In its obviously Early, very early stages. And was no doubt expensive. But You know, the difference in fit and finish and the appearance of the casework of your two products. And I know they’re 20 years apart or 30 years apart. So not to be compared, but it’s something that. I don’t want to go on about it, but the aesthetics have got to be right if you’re going to sell high quality, relatively expensive Products worldwide. And That’s where Peter didn’t quite get the me up to that standard, I think. Although the standards at the time were much different to what they are now. But I mean his amp sounded fantastic and actually were you know, very reliable as well. And
Jon says some of the best cars sell because they look amazing
And But they weren’t pretty. And Your product is. So I just wanted to say that. I mean, it sounds kind of pathetic in a way, but it’s just. It’s an important piece of the puzzle. And If you consider some of the utter rubbish that sells that everyone loves, it’s partly because it just looks amazing. They’ve spent most of the money on CNC. Have you got some thoughts on that, Jon? At all? I know we’re jumping away from the history lesson a little bit, but I mean, you know, it seems that your product is as high tech and as thoughtful inside as outside. But you’ve got to have both. And you’ve got both. And as you said, you didn’t originally have that until you’re Fortuitous CNC friends. You know, they’re getting together with him.
Jon De Sensi: Yeah. Yeah. Yeah. Exactly. Exactly. Yeah. We You know, look, I’m a good designer and a good builder, but I’m not great when it comes to aesthetics. But I. You know, we did have, you know, the longest COVID lockdowns in Victoria.
Andrew Hutchison: Yes, you did.
Jon De Sensi: In the world. And so that gave me a lot of time to kind of think about the new designs. And I just wanted to create something that was going to, you know, have so much eye candy, but be classy.
Andrew Hutchison: Yeah.
Jon De Sensi: and you know, would just interest people because there are just, you know, there’s no time in the history of the world, where there is, you know, so many components available now. There’s so many choices.
Andrew Hutchison: Yeah.
Jon De Sensi: And you really need to kind of stand out, from the crowd if you want to at least get someone, you know, to pique their interest. And I thought, I just can’t do another
00:35:00
Jon De Sensi: plain front panel. So we we, we got some custom made meters, and look, you know, for the most part, unless someone’s got, you know, which no one does perfectly. Eight ohm, speakers, flat speakers across the audio band that they really are just cosmetic. And then you know, just something, a bit of bling. But
Andrew Hutchison: It’s great bling. It’s very good. Bling.
Jon De Sensi: Yeah, but it is, it is good. And and I think, you know, it really works with m, the proportions that we’ve chosen. and it’s just that, you know, I mean I’ve, you know, it sells ridiculously inexpensively, really, considering how much work goes into just the chassis. But I have had people say, you know, that looks like a 40 km Jon. And That’s the best compliment that, you know, I could ever ask for.
Andrew Hutchison: Yeah. So, and I would concur and just, just on that subject of the chassis.
So the front panel is beautifully CNC machines, obviously, you know
So the front panel is beautifully CNC machines, obviously, you know, solid piece of aluminium, but the, and beautifully finished off and inscribed. And of course you’ve got those beautiful vu meters etcetera. But what, what, all very beautifully executed aesthetically, but the chassis is then A solid chunk of alley that’s all machined out. Or is it pieces screwed together or please explain, you know, what?
Jon De Sensi: Yeah, yeah. So they’re all pieces that are joined together. So the front panel of the power amp is 16 mm in thickness. the two side panels which are machined into heat sinks that straddle the whole length. they’re actually billets of 50 millimeter aluminium. So there’s a lot of. Lot of aluminium, a lot of weight.
Andrew Hutchison: Yep.
Jon De Sensi: And, and Top and bottom panels are A quarter inch.
Jon De Sensi: sorry. 6.35. Yeah, 6.35. They’re quarter inch machined. so the front panel actually It dowels into the side. heat sinks.
Andrew Hutchison: Okay.
Jon De Sensi: So it locks it in and lines everything up. So it’s just you know like millimeter perfect.
Andrew Hutchison: Yep.
Jon De Sensi: And then there’s screwed. Well actually, yeah, probably a hundred. Yeah, exactly. And then they’re screwed as well from the inside. okay, to you know, anchor the front panel onto the heat sinks. and then the, the top panel has ten screws that screw in into the heat sinks. And the front panel, and the rear panel. And the same with the bottom panel.
Andrew Hutchison: And all of that sounds a little bit like a meccano set except when you see it assembled and finished, it’s it’s anything but. It just looks well it looks hewn from the solid, really. And it’s just like going on about it. But it’s completely impressive.
We’re going to talk about amplifiers and preamps and power supplies
So we’re going to have a quick break and come back and talk about two things. One, I know Brad’s got a question about transistors, but, and we’re going to. So we’re going to talk about what’s inside the amplifiers and touching preamp briefly and talk about all in all important power supplies. Everyone’s concerned about power supplies these days. And and also just finish off that, that music lab story of sort of how you got started in the Because I just sort of jumped away from that, which I shouldn’t have. We should have finished that story.
Brad Serhan: But the music labs one is a, is a good one.
Andrew Hutchison: So the music labs and the What’s inside and Also tell us about the preamp and the power supply. So four things really. So thank you folks for listening this far. we’re just going to get into the good stuff now and we’ll be back in a second with Jon Desenzi from OAD Labs. OAD Ultrafidelity in fact. And of course Brad from Sir Hannah Swift. Hey, thank you for listening to the Not An Audiophile podcast. It’s very much appreciated. We’d love your feedback. Like follow comment, share all of that sort of stuff. certainly comments on YouTube. We’re on YouTube. Fire away. Tell us what you think and we’ll, we may even answer you back. So yeah, thanks again for listening. this was the ad break. Back to the show.
Jon Desenzi talks about Melbourne-based CNC manufacturer
Hello folks, we’re back. segment two of Not An Audiophile with Jon Desenzi. and Brad Serhand, assisting myself, Andrew Hutchison. Now this is a, it’s a great conversation because this amplifier or amplifiers because there’s a phono amphennesse, phono priest amp, a normal line preamp and ah a power amp in Jon’s range, OAD Ultrafidelity. And we were discussing how carefully machined and how world class the product looks. And we’re about to discuss the insides. But before we do that Jon I’m just interested to know how you, you said you hooked up with a guy who was into CNC and and also had a love of audio. So sort of a match made in heaven that you’re good friends. But just how good is, is their machining and what else does this company do that you know, I mean is it a big business?
Jon De Sensi: yeah the business is huge. It’s Melbourne based,
00:40:00
Jon De Sensi: it’s still owned by a family business. It started in 1974. And They literally make the best grinding machines and CNC systems, on the planet. And
Andrew Hutchison: On the planet. That’s a bold claim, but Let me guess, you’ve got a trinket of information that might back that up.
Jon De Sensi: Well look, I know that lots of countries have tried to copy or tried to equal what they’re doing and they haven’t succeeded. to the point where like even in just prior to the iPhone release of course the very first iPhone, Apple or Foxconn, who build the Apple iPhone actually could not build their, their particular case, their metal cases. Metal yet metal chassis, without Anca tooling. And so they received a very large amount of money to provide tooling to build anchor.
Andrew Hutchison: Anca Tooling being the company you use for your CNC work.
Jon De Sensi: Correct. Same company.
Andrew Hutchison: Yeah.
Jon De Sensi: Yeah, yeah.
Andrew Hutchison: So they. Sorry, they were. What were they making for Foxcon that make the iPhone?
Jon De Sensi: well they were making all of the little you know, I guess tools and they be. To shape aluminium to make the iPhone case essentially.
Andrew Hutchison: Wow. Okay so let me get this straight.
Jon De Sensi: To the, to the precision that it needed to.
Andrew Hutchison: Yes, yes. So that it just clips on so perfectly. To the. Yeah, to the chassis. So are you. So you, so let me get this straight. So Apple who obviously subcontract the construction of their phones out to this chinese conglomerate, Foxconn. Foxconn comes to a Melbourne company that you, that you use for your own amplifier construction because they are the best in the world and the only company that can actually make this thing to the precision that is required for an apple correct. Wow.
Jon De Sensi: Correct. That’s.
Andrew Hutchison: That’s something.
Jon De Sensi: That’s, that’s the verified story.
Andrew Hutchison: Wow.
Jon De Sensi: And Yeah they’ve got a massive research and development arm which keeps them you know, a few steps ahead of their competition. And they literally are a market. Market leader in In what they do.
Andrew Hutchison: Wow. Okay.
Brad Serhan: And it’s amazing.
Andrew Hutchison: It is amazing. And it’s, it’s just, it’s just, it’s almost like sometimes you say ah, we don’t do anything in Australia anymore. There’s no manufacturing, blah blah blah. Actually there kind of is. That’s I mean I can think of a few others as well, but that is That’s quite something. And so do they do other you know, super high tech, high precision stuff for other overseas concerns?
Jon De Sensi: M look, most.
Andrew Hutchison: Yep.
Jon De Sensi: But not that I’m aware of. I haven’t really taken a. You know, a good. I mean they keep a lot of it to their you know, close to their chest.
Andrew Hutchison: Okay.
Jon De Sensi: Yeah. As they would. But this is one story that I’ve heard you know, time and time again from family members. It’s still a family owned company and from employees. So
Andrew Hutchison: Yeah they must be Pretty, pretty proud of that. And But so really when I. So when I glanced across you know, saw your product for the first time, I thought wow, that is, that is something that I wasn’t mistaken then. So it just happens that perhaps the best CNC machining company in the world did the work. So that would help to explain that incredible fit and finish. Alright. Thanks for that. So. So let’s take the lid off now and move inside.
So you have this history of modifying Sansui amplifiers and then suddenly
So you have this history of modifying Sansui amplifiers and then suddenly. No, not suddenly at all. Clearly your knowledge You’ve tried all sorts of things and we’re going to round up some of that history in a second. But But you know skipping forward nearly 30 years, you’ve obviously honed the development of the amplification circuit as well. And was there a refinement to get to this Final design in the, in the super casework? Was this a new or tweaked design or clean sheet of paper or was it actually just a development of something you’ve been doing for ten or 15 years?
Jon De Sensi: yeah, it was a development that Of continual improvement over the last 30 years. Essentially 30 years. So Our amplifier is unique in that just about every And I still do a lot of high end servicing of amplifiers which I prefer not to do but we.
Andrew Hutchison: All prefer not to do it.
Jon De Sensi: Yeah, yeah. Unfortunately it’s going the way of the dodo, those sort of people that can service high end audio gear. but virtually every amplifier I’ve seen, uses like common emitter output, stage, amplification, I’ve never done that, including with the music labs as well as the OAD.
00:45:00
Jon De Sensi: So we flip the transistors around and So rather than I mean there is a little expense to be paid which is a little bit, slightly higher output impedance but it’s not a big deal and damping factor certainly isn’t an issue. And And the reason for that is you just get a more linear output stage. you know, a diode is a nonlinear junction and You know, whilst you can bias, you know, common emitter amplifiers, so they’re fairly linear. They’re never going to be quite as linear as flipping the transistor around and using it as an amplifier, which is what the transistors were originally intended for.
Andrew Hutchison: So. So you’ve got collector resistors instead of emitter resistors. Is that the, Is that how it works?
Jon De Sensi: Yeah, yeah.
Andrew Hutchison: Okay. Yeah, yeah, yeah that’s
Jon De Sensi: Yeah. Well we do have them in the collectors as well, but that’s just to balance all the currents between the output transistors as well. make sure they’re all getting an even amount of current and not just relying on a production run of, you know, the internal resistance of the base emitter junction. Yeah, yeah.
Andrew Hutchison: So. Sorry. Yes, you may have meant to say emitter. So you got both emitter and collector resistors.
Jon De Sensi: Ah, sorry. Yeah. Emitter and collector.
Andrew Hutchison: Yeah. Okay. Yeah.
Jon De Sensi: But, but our collectors go through a 0.1 ohm resistor, to the output.
Andrew Hutchison: Yeah, yeah. Obviously the emitter resistor is a few ohms or whatever it is. Ten ohms or something.
Jon De Sensi: I don’t know what actually. It’s, it’s only 0.1.
Andrew Hutchison: Oh, it’s tiny as well.
Jon De Sensi: It’s the same, yeah, yeah.
Andrew Hutchison: So that’s okay. So completely different configuration. But you know, bipolar transistors, no mosfets here is that, that’s Which is fine. But
Jon De Sensi: There’s been a lot of debate that people in the know would know about over the last 40 years. people like Douglas self, from the UK and Edward M. Cherry from Melbourne University who’s a very fine amplifier designer. I’ve had lots of debates through wireless world and other magazines, about which is better. And I’m with Douglas self and believe that and have tested that a bipolar transistor is actually more linear than a mosfet.
Jon De Sensi: And you don’t have the high input capacitance that audio mosfets tend to have. So I think overall they’re they’re Just a better choice these days.
Andrew Hutchison: Well I feel like transistors, bipolar transistors have moved forwards with many iterations over the last 30 years. And mosfets are sort of. Well for audio amplifier outputs. I mean there’s plenty of mosfets around. I mean as far as for controlling motors or something. But
Jon De Sensi: Yeah.
Andrew Hutchison: But yeah, for audio.
Andrew Hutchison: They haven’t been flavor of the month for a good while, have they?
Jon De Sensi: No they haven’t. And they’re actually Almost impossible to find now.
Andrew Hutchison: Yeah.
Jon De Sensi: Like since Toshiba and Hitachi Or Toshiba no longer own their semiconductor division that’s been sold off and they don’t make them.
Andrew Hutchison: Okay.
Jon De Sensi: And Hitachi before that
You use bipolars and transistors in your amplifiers. And look, they’re 30 years apart
Stopped you know, years earlier. Oh that’s right. Yeah.
Andrew Hutchison: She were the. Those early ones, the
Jon De Sensi: Yeah.
Andrew Hutchison: The back in the eighties. Yeah. But the eighties ones when it was a When Mosfet amps were the go for. Well for quite a few years really. I mean they were. And I mean was that, was there more to it then? Was there? I mean they’ve got, they’ve got quite a charming sort of sound. But they always feel like they’re a bit doughy sounding compared with a Bipolar transistor. Is that, is that youre thought or what’s.
Jon De Sensi: I mean yeah actually I repaired Repaired an amplifier. I think it was a plinius actually. From 1987.
Jon De Sensi: About a year ago, yeah. And You know I set it down in the system and it was a really, really pleasant sound. It was actually really quite warm.
Andrew Hutchison: Yeah.
Jon De Sensi: It did sound more like a tube amp. But it just lacked complete detail. And Well you know, detail compared to what I’m getting out of my ad.
Andrew Hutchison: Well yeah. Which is obviously Fairly heightened level. But
Jon De Sensi: Yeah. And look, they’re 30 years apart as well. And you know, I’m using state of the art components and they’re using state of the art back in 1987. And things have moved along. Yeah. It was quite a different sound. And if you like that sort of sound, if you don’t, if you’re not after an accurate sound. And look, you know, there is no right or wrong. It’s just whatever people you know, whatever they’re attracted to.
Andrew Hutchison: Absolutely.
Jon De Sensi: Yeah. Yeah. But I listen to a lot of live music and so I tend to try and, you know, make amplifiers that mimic m m that. And, Yeah, I mean, it was really lovely to have it here for a few days, until the customer picked it up, because it was just so different. And, I could see the attraction towards it. But then I could also hear, you know, exactly the differences between bipolars and transistors
00:50:00
Jon De Sensi: that I’ve, you know, had experimented with over the last sort of, you know, 40 years as well.
Andrew Hutchison: Yeah. So you.
Jon De Sensi: And look, you’re quite correct about the bipolars. They’ve come a long way in, recent years. there’s a development of a new transistor for audio called a thermal track.
Andrew Hutchison: Okay.
Jon De Sensi: Which actually has five pins. Ah.
Andrew Hutchison: Ah, those things. Yes, yes, yes.
Jon De Sensi: Yeah. So they’ve embedded a diode, which is electrically isolated, but, thermally, not. And, they’ve taken bipolars to a completely new level, which is what we use.
Andrew Hutchison: Oh, you do use those? Okay, yeah, actually we do. Some reason I thought those five pin devices had faded from popularity. But I’m, probably thinking of an earlier one. there were others.
Jon De Sensi: There were others? Yeah.
Andrew Hutchison: Yeah. But yours. Okay, so you’re using those devices, which I have seen in some pretty fancy amplification.
Andrew: You’re very concerned with class. Jon: Well, it’s more about class
Now, Brad’s got a question, that he wants to ask. I believe Brad’s phoning in from Sydney. Hello, Brad.
Brad Serhan: hello again, Andrew.
Andrew Hutchison: Something about classes. You’re very concerned with class.
Brad Serhan: Well, yeah, I’m Not the sort of class we might think about in society. Necessarily. Necessarily.
Andrew Hutchison: Well, it’s more about class.
Brad Serhan: Yeah, we were egalitarian, supposedly.
Brad Serhan: well, I just do speak at side and my memory from my electrical engineering is poor. So, explaining the sort of. Some people extol the virtues of sort of running fiber, of class a power. But, I asked Jon the other day about this. And he explained to me how he works it with class a and class A b. And, If you remember my question, Jon, you might be better to ask the question of yourself and then explain it. I played soccer this morning. I’m a bit tired. So there you go. That’s my excuse.
Andrew Hutchison: That’s right. Well, I mean, I guess the word has it that your amplifier, Jon, is, Biased heavily into class a. And delivers a decent useful amount of power with zero crossover distortion. Is that the case?
Jon De Sensi: well, almost. Considering that the. Relative to the power output that the power amp can put out, then it’s. Then it’s not heavily biased into class a. But it is from another point of view in that, despite what most people believe, you know, most people are listening between sort of five and ten watts of sort of average power going into their loudspeakers.
Andrew Hutchison: Yep.
Jon De Sensi: you know, even with, you know, just under 90 decibels, Spl speakers, you know, most people are not really getting hundreds of watts into their speakers despite the fact that they think that they need an amplifier that powerful. So what we do?
Andrew Hutchison: You make them?
Jon De Sensi: Yeah, well, I keep getting asked to make more powerful ones.
Andrew Hutchison: Oh, do you really?
Jon De Sensi: Yeah, because there’s a. Not because of, You know, they’re going to sound better. It’s just because there’s a. There’s an arms race out there and people think the more powerful an amplifier is, the better it’s going to be or the more impressive it is and they’re willing to pass over their money. You look at another fine australian company, Halcrow.
Andrew Hutchison: Yes.
Jon De Sensi: Who make a 40,000 pound, which is close to $100,000 australian power app. And their power output is 180 watts per channel, the same as what we make.
Andrew Hutchison: I was going to say yours is about.
Jon De Sensi: Yeah, yeah, that’s a sweet spot. It’s a real sweet spot between reliability, using, you know, the fewest number of transistors, which will always sound better than using more transistors and trying to buy, bias them up and having the parasitic oscillations that you might get. And there’s all sorts of other complications.
Andrew Hutchison: So how many devices per rail are you using per channel?
Jon De Sensi: So in each channel there’s two devices per rail.
Andrew Hutchison: Okay.
Jon De Sensi: So for four transistors per channel. Yeah, yeah.
Andrew Hutchison: So that’s I guess that’s quite typical. And that’s a good balance between power output and not having extra devices, which just complicates things and muddies things up, I guess, and, you know, obviously and complicates things as far as the circuit. So. So, yeah, so that’s, So 180 is a sweet spot we were talking about. So what do you think then you’ve got, what’s the power output in true class A then of your amplifier?
Jon De Sensi: So we bias them to about ten watts of class A. Yes. So for most people, they’d be listening into class A. But even beyond that, it’s, it’s not really an issue if you, if you’re using these thermal track transistors. Because, one of the things that they do by having the diode built in is that you can get Like massively
00:55:00
Jon De Sensi: increased, like Settling time and bias stabilization in the output stage. And what happens is that you tend to get even in class Ab. And I’ve measured this with the audio precision, you will get class a type distortion figures out of a class ab.
Andrew Hutchison: Using those, using the thermal track devices. Yeah. Okay.
Jon De Sensi: Yeah. And using the thermally integrated bias diodes.
Andrew Hutchison: So that’s a, so that’s a key part of your design. is those particular devices, is output devices.
What about power supply? I mean everyone, I mean we mentioned Peter Stein
Is there any other, you know, is there any other. I mean, I know there’s other tricks, but what are the other handful of key things that You feel strongly about? I mean you clearly feel strongly, feel strongly about a fairly simple, output stage. What about power supply? I mean everyone, I mean we mentioned Peter Stein. He was a lover of paralleled, up smaller value electros, rather than two, just two giant whopping bucket sized ones. What Do you have thoughts on that at all?
Jon De Sensi: I do, I do. I mean any audio. Well, every audio amplifier, what it’s effectively doing is modulating the power supply voltages.
Jon De Sensi: So the better and the cleaner and the more ideal the power supply is. then you’ve got more of a chance, provided your audio amplifier is a good design to give you the best type of sound. So we Currently in the Vajra, we do use just a conventional toroid. it’s almost 1, which is grossly overrated. It’s a hefty transformer for a 180 watt per channel amp. but then we use I know we were the very first, but, and we may still be the only company. And the reason why we can do this is because we’re very small, I guess, and we can, you know, change things very quickly. and we. So what happens is some, some m clever people in the UK years ago, worked out that you get eddy currents that circulate in the foil of an electrolytic.
Andrew Hutchison: Yeah.
Jon De Sensi: capacitor in audio use. So they come up with this clever idea of actually putting a slit in the foil so that you would break that circulating current.
Andrew Hutchison: Yes.
Jon De Sensi: And they swore black and blue that you get better mid m range and better top end.
Andrew Hutchison: Yeah.
Jon De Sensi: Because you don’t have that eddy current sort of modulating the DC that’s, that’s there.
Andrew Hutchison: Sure.
Jon De Sensi: So it all makes, you know, sense. but unfortunately they went on to make capacitors that weren’t high enough voltage to be used in, in big powered, amplifiers. And then, a couple of years ago, m a giant american company, started making, 80 volts and 100 volts electrolytics with the slip foil technology, in the EU, and so we quickly switched to those from our old models to the new models because they came out as we were just building. Yep, the first set. And, and I think they’ve made a massive improvement. They’re also, you know, a lot bigger than what we’ve used in our older models, so that they see stabilized even better. Yeah.
Andrew Hutchison: So just one big capacitor for each rail, or.
Jon De Sensi: No, there’s a few ganged up. So Peter Stein was correct. And in the music labs, we used a whole lot of very small ones as well. and the idea of that is that, smaller caps are faster than bigger caps. Also, smaller caps in parallel reduce the output impedance. And they’ve got a lower output impedance to begin with because they’re smaller than a big cap. lower output impedance just starts to emulate more of an ideal power supply. in the Vadra, we use twelve of these slip foil caps. so six.
Andrew Hutchison: Quite an array. All right.
Jon De Sensi: Yeah, yeah, yeah, yeah. And they’re, I think they’re 6800. No, they’re 10,000 mike each. So that’s okay. So tons, 60,000, yeah. Per side. A lot of capacitance. and,
You say there’s a slight monoing effect with stereo power supply
Andrew Hutchison: Is that a stereo power supply or, a mono effect? I mean, that’s, that’s the wrong terminology.
Jon De Sensi: To use, but, yeah, you’re right that the power supply is shared between the two. So, you know, internally.
Andrew Hutchison: No. Do you feel that that’s, I mean, there’s. Some brands are big on that and, others could care less. have you. I mean, you’re saying the power supply is an integral part of the signal, so we got some slight monoing effect because we haven’t got a separate, you know, AC DC power supply section. Or is it, you think it’s negligible?
Jon De Sensi: look, it’s really interesting. I used to have people ask me, or probably still do, actually saying, when are you going to bring out monos?
Andrew Hutchison: Yeah.
Jon De Sensi: And I’d often say, come, over and we’ll just like, we’ll bring out two stereo, one channel.
Andrew Hutchison: Yeah.
Jon De Sensi: And then they take them home as well. And, and we’re all in consensus that actually, every time we just ran the stereo amp as a stereo amp and not run it as a mono and have two of them just sounded better every time. And I still don’t know why that’s the case.
Andrew Hutchison: Yeah. That’s odd, isn’t it?
Jon De Sensi: But I mean, they said that with the monos you tend to get. If you’ve got demanding speakers, you might get a little bit better. The bass extension. But as far as the rest of it was concerned. Like the musicality and the mid range. Critical mid range sort of frequencies that everyone, including myself, you know, we always.
Jon De Sensi: Preferred the. Stereo amp.
Andrew Hutchison: Well, that. That’s That’s a. That’s a very interesting observation. So, I mean, you would think maybe using two amps and using a. You know, half of each. One for each left and right. You know, one for. You know, one for left, one for right speaker. And then obviously there’d be a bit more power supply for each channel. Effectively.
Jon De Sensi: Yeah.
Andrew Hutchison: If it was required. And And that it couldn’t sound worse. But you. But, It may not sound. It may not sound much better. But it can’t sound less good, surely. And yet that’s. That’s the thought. That’s almost. Bias. Sort of, In reverse. In the sense of you’d set yourself up for it to be better and you convince yourself it was. But in reality, no, not in this. And so both various clients or associates that have tried that. And yourself all agree that the mono. Sorry. That the just one stereo amp m. Sounds better than two monos. Which of course would be better than two mono blocks for that matter.
Jon De Sensi: Yeah. Yeah. You know, it. It’s. That’s exactly what we all found. I don’t know whether that’s just with my amps. Because I haven’t tried it with any other amp. But I think part of the reason why I think it does sound better is with the monos. The sound. The sound in the middle just seems to.
Jon De Sensi: Not. You know, it seems to disappear a bit. Whereas with the stereo. Probably because the two channels are sharing the same power supply. And there’s a little bit of crossover. It fills the middle. And so you’ve got this seamless, Wall of sound from left to right. And that’s why I prefer it. And why they preferred it as well.
Andrew Hutchison: Yeah. That’s interesting.
Jon De Sensi: So, monos.
It just sounds like a dual mono recording off an lp
Yeah. It just sounds like a dual mono recording off an lp or something. Where. Which you hear great sound in both channels. But it just doesn’t.
Andrew Hutchison: Yeah. So. Yeah. So it’s a thing. It’s not so much detail in the mid range. It’s just the way the stereo gel. Is that the thing?
Jon De Sensi: Yeah.
Andrew Hutchison: Yeah.
Jon De Sensi: I think that’s what I’m, that’s what I was noticing. Yeah, absolutely. Absolutely.
Andrew Hutchison: Very interesting.
Jon De Sensi: Still don’t completely explain, understand it, but that’s, that’s, that’s what I’m hearing. Yeah.
Andrew Hutchison: Okay. Yeah.
So input, um, uh, stage to the power amp is traditional
Well, moving, moving on. So input, stage to the power amp is traditional, or have you got some interesting, Yeah, differential pair arrangements or something, or.
Jon De Sensi: Yeah, we probably do something. I’m not, not a different arrangement. It’s a fairly standard differential pair. But unlike again, most amplifiers, that I’ve seen over the last 30, 40 years, we, I mean, the Japanese were doing this really well back in the old days. But again, now that Toshiba’s not making transistor, audio transistors, you can’t get really good pairs anymore. But we, we do use a super matched, bipolar input, differential pair. So they’re actually on the same substrate and they’re thermally matched. And the idea for that is that we didn’t want to like use a DC servo loop, and we wanted to obviously minimize any dc, because our amps at DC couples literally zero to, you know, 200k.
Andrew Hutchison: They’re DC coupled. So you need extra, you know, you need good thermal stability, I would imagine. And, to keep that DC voltage, to close to zero as possible. And so I didn’t even realize they were still making, input pairs. Super matched pairs, yeah, that’s, so that’s the thing. Still comes in one package with what, five legs? Is that the, or is it not like, the old ones?
Jon De Sensi: Six legs.
Andrew Hutchison: Yeah, six legs. Okay.
Jon De Sensi: Yeah. Well, you know, two bases, two emitters, too.
Andrew Hutchison: Well, yeah. Not some. Not common, What was the common one on the five pin ones? I can’t even remember. I mean, you know, hey, I’m just a technician, okay?
Jon De Sensi: Oh, you’re talking about one that had the bases.
Andrew Hutchison: Yeah. The two SA 798 or whatever that had, Yeah, bases.
Jon De Sensi: My apologies,
01:05:00
Jon De Sensi: my apologies.
Andrew Hutchison: Yeah. But yours, so the ones you’ve got are literally two transistors on the same substrate in the same plastic molding, six.
Jon De Sensi: Legs at the bottom of it, which are absolutely identical. Now, there’s a, there’s still a lot of those sort of transistors made, but they’re not audio quality, as in they’re noisy.
Andrew Hutchison: Oh, okay. Yeah.
Jon De Sensi: And they’re the, you know, that they’re made for, you know, companies that might be using it for different, you know, non audio applications. But there’s a, there is a company, thankfully, in the US, in California called linear systems. And they make a whole range of very high quality bipolars and fets, and they also get their hands on obsolete, equipment, like Toshiba. And they remake transistors that audio transistors that were once incredible. And they actually make, make them better that like they actually. I don’t know how or why they actually make them to a higher spec. So thankfully there are companies like that, that have, you know, seen a little niche in the market.
Andrew Hutchison: That’s, it’s just amazing. You’re What else is amazing is that you, feels like you’ve, there’s a lifetime. Lifetime, ah. Of work and research to find all of these suppliers. Because it’s not like you’re, it’s not like you’re putting an order in with digikey, by the sound of it, or let alone, going down a j car to pick up some.
Jon De Sensi: No, it’s. Look, I’m, I’m on so many different, I’m on so many different newsletters for components.
Andrew Hutchison: No doubt. Yeah.
Jon De Sensi: And there’s probably lots that I, that I miss out on that.
Andrew Hutchison: Don’t say that. Don’t admit to that. You, you’ve, you’re on top of it. You’ve got the best of everything.
Jon De Sensi: But, yeah, I do, I do seem to come across the right component at the right time. And yeah, it’s, and it’s, it all works as a synergy. And I’m really, you know, excited about, you know, the sound, you know, that we get out of amplifiers.
Andrew Hutchison: Yeah. Yeah.
The volume control is probably the key engineering
Well, the preamp. Okay, without a preamp we can’t. Yeah, we’d have to listen to it flat out the whole time and only have one input. So what what what’s going on in the preamp? That’s, that’s I mean, I think I would guess that the volume control is probably the key engineering, tour de force there.
Jon De Sensi: Look. It is, it is the. So the preamp, we, our earlier version had a touchscreen, which was actually, from a practical point of view, I think, a lot nicer, to use and a lot more flexible. But when we redesigned the preamp, we thought we’d go to a more conventional looking preamp and something that, you know, you could look at in 25 years or 30 years and say, wow, that’s, that’s a classic. It still looks really good on the eyes.
Andrew Hutchison: Yeah.
Jon De Sensi: And it’s not going to date, anyone who’s been to the website, you know, might have that opinion. so, But yes, you’re right, the volume control, is really quite sophisticated. In fact, in many ways, the preamp electronics is more expensive to manufacture than the power amp. The reason being is it, uses a dual shaft stepper motor. So it’s got the shaft out the front where the volume knob is actually mounted, but it has a shaft out the back. And so, people probably aware of the term fly by wire. So, you know, modern cars don’t have a steering column that goes all the way down to the wheels anymore.
Andrew Hutchison: well, actually, on that front, well, I mean, fly by wire throttle, we know about. There’s no throttle cable operating a carburettor. Or, for that matter, the, intake. the throttle bodies, right? yes, the steering. The steering by wire thing. Which aircraft like that for a long time, I guess. But the, I think Airbus started that. But the, The, new, that stupid looking, elon invention, the, tesla. The. Yeah, not. Yeah, but the specifically cyber truck. The cyber truck. Yes, the cyber truck. What a. What a wonder. It is, biggest step back in automotive design ever. Ah, but, yeah, but on the other hand, it has steering, by wire, which I didn’t know would even be legal. So, there’s other cars that have that as well. I have a vague feeling a Volvo had it as well. But,
Jon De Sensi: What?
Andrew Hutchison: I’m gonna go sideways, but there’s a few that have got it. Is that right?
Jon De Sensi: Oh, I think you’ll find probably every car made in the last 15 years, maybe even 20 years, is fly by wire. Now, in other words, they don’t have that steering column that goes all the way down, that mechanically turns the wheels. They actually have, like a magnet that, in fact, they’ll have several of these for redundancy, of course.
Andrew Hutchison: Yeah.
Jon De Sensi: Because if one of them fails, you’re going to lose your steering. but they literally, there’s a magnet that actually,
01:10:00
Jon De Sensi: turns in sync with the steering wheel. It’ll have a chip that, is literally a millimeter of air gap away from a neodymium magnet. And it actually, will actually read the rotation, incredibly accurately. like, you know, below 0.1 of a degree, they can do. Not that you’d need that for a cardinal. And then that feeds up to a micro processor. Micro processor then actually controls a motor that actually turns the wheels, believe it or not.
Andrew Hutchison: Yeah. Okay. Now, I wasn’t aware of that. And I have some interesting cars, but I also suspect that maybe there’s some mechanical redundancy there. And the difference with the Tesla is that it’s just not connected in any way. If the battery goes flat, you crash. Maybe not quite like that. The battery’s not going flat anyhow. It’s got plenty of battery power. but yeah. Okay. So your volume control uses this technology. So it’s not, it’s coupled but it’s mechanically decoupled. Is that the point?
Jon De Sensi: Yeah. Look, this is all just so that someone can control a knob for the volume if they’re going to be walking up to the preamp rather than just use the remote. Yeah. It’s not actually needed for the remote. But of course when you use the remote you want to see the knob turn because otherwise they won’t match what you’re actually. No, what volume you’re actually at.
Andrew Hutchison: Yes.
Jon De Sensi: So it’s a lot of It was a lot of work. It was two years in development. There’s literally over 20,000 lines of code.
Andrew Hutchison: Oh wow.
Jon De Sensi: written to. And it’s just simply for, you know, to show you. And of course you can control the volume from, from the front panel knob. Volume knob. and yeah there’s a whole lot of 3d printed plastic that actually mounts to the rear of the stepper motor which holds the magnet in place and holds a circuit board that has the, you know, the chip that actually senses the rotation and that feeds that all back to a microprocessor. Once the microprocessor knows exactly where the volume knob is rotated to it actually then feeds a signal out that goes to, to literally you know, right to the back panel, the rear panel where there are two audio files. I think they’re the only, I’m pretty sure they’re the only audiophile grade r ah, to r ladder volume chips on the planet. And there’s a little story behind that. So ah, many years, a few years ago two japanese employees begged their bosses to make an audiophile grade r two r ladder DAc because they were sick of using relays and resistors.
The best preamplifier in the world is made at your factory
And so in the size of about half, of half a postage stamp, they made these little chips that are incredibly accurate. They’re all laser trimmed resistors. They’re all thermally you know, connected together. They also have a zero temperature coefficient so they don’t drift. and they are literally you know, transparent to the sound. They just they do their job but they don’t get in the way of the sound. The story is they also sent some to Nelson Pass. And Nelson Pass was so blown away with them that they ended up using him in only the top model, pass labs. preamps. Of course, we’re not talking about american preamps, so we’ll get back to.
Andrew Hutchison: No, no, clearly the best preamplifier in the world is made at your factory. The We’re not biased at all. Such an impressive story though. So you’ve got the best attenuator chip, on the, on the planet. And that I guess that’s controlled by microprocessor that’s also controlling all of this other stuff as far as the making the knob turn and what have you. yeah, and you know, obviously you’ve got input, switching and you know, commands coming in by remote, etcetera. it’s. Is there, is there a aspect to the circuit that obviously a little bit of buffering and amplification that’s involved? Well, for that matter, how does the input switching happen? Is that little relays or is it a some other even better way to do it?
Jon De Sensi: No, we are using high quality signal relays with silver contacts. and again, they’re right, behind or alongside the RCA inputs, which are all PCB mounted. So we’re just trying to keep the signal path as short as possible. And then the volume chips are right there as well. there’s no buffering that’s required. It goes through, the inputs get switched and then whatever signal is switched goes through, the volume control chip. And then the volume control chip then goes into our discrete op amp design. and we have four discrete op amps, two
01:15:00
Jon De Sensi: on a board, and one’s for inverting and non inverting. So this is a true balance that’s not using any, balance. The single ended. Single ended to balance chips that you find in a lot of high end gear as well as most tube amps because you don’t have like a p and an n version of a tube.
Andrew Hutchison: No, there’s no balance. there’s nothing balanced in the tube world, is there? Just Am I right or wrong on that?
Jon De Sensi: Well, not as far as a tube, but you can use transformer, of course. But of course on one side of that transformer it’s going to be single ended.
Andrew Hutchison: Yeah.
Jon De Sensi: so it’s never going to be true balanced, unless it’s passive. whereas in my design it is literally true balanced all the way through.
Andrew Hutchison: Yeah. So, okay. That’s.
Jon De Sensi: So this is a four discrete op.
Andrew Hutchison: Amps, so I can’t.
Jon De Sensi: Yeah, and look, and they’re. And they’re removable. They’re plug in. So you can actually replace them with better, you know, models down the track, if that ever comes to be.
Andrew Hutchison: Be. So. Yeah, just I have,
How do you sell the Padma? I don’t know how
I feel like, the piece of the puzzle that we’re probably ignoring, having had you brief us on the fact that this thing is, an incredible amount of thoughts gone into it and it’s clearly, world class both on the inside and the outside. What, How do you sell them? I guess they’re sold around the world or in certain. In other countries other than here. But, What sort of ballpark money are we talking? Because they’re not supersonically expensive, are they? As my memory serves me correctly, no less than the price of a concord is what I’m implying. Well, I mean, I’ll let you speak, but. Yeah, I don’t know how you sell them and, I want to hear about that because ultimately that’s what you make them for, I guess, is to, Other than it’s not just for your own amusement. no, although at times it may feel like that, but, Yeah. So how do they sell and ballpark money, sir.
Jon De Sensi: Yeah. So, the recommended retail for the Padma is 10,000 australian dollars.
Andrew Hutchison: What?
Jon De Sensi: for the prim, for the print.
Andrew Hutchison: So ten grand? Hang on.
Jon De Sensi: Yes.
Andrew Hutchison: So it’s got all of the stuff with that. We just discussed the best of this, the best of that, the best machining. The best. Yeah. Ten grand. Okay, so why does anybody buy anything else that’s in. That’s. That’s amazingly good value.
The param is $15,000 retail; the power amp is $50k
All right, and what about the param?
Jon De Sensi: yeah, and the power amp is. Is $15,000 retail? Yeah. You gotta be joking.
Andrew Hutchison: So. So the guy who said it’s worth 40 grand, I take it. Well, he should have bought one, shouldn’t he? $15,000.
Jon De Sensi: That’s, Well, look, if it was made by. If it was made by any other high end company, the combination would probably be around that sort of 40, 50k.
Andrew Hutchison: Yeah.
Brad Serhan: At least.
Jon De Sensi: They’re very, Yeah, they’re incredibly inexpensive.
Brad Serhan: Incredible value.
Andrew Hutchison: Yeah, incredible value does that. Okay, so sorry, Brad way.
I’m using Jon’s previous model, param. He loaned it to me six months ago
Again.
Brad Serhan: Maybe it’s not the right time to mention this, but I’m using, Jon’s previous model, param.
Andrew Hutchison: Yeah, I.
Brad Serhan: He loaned it to me just six months ago and.
Andrew Hutchison: Oh, did you send him an email saying, I’d like some cheap equipment, please, and Jon?
Brad Serhan: No, I did. You know, I don’t communicate by him. I was like, I’m, I’m Holly, although I’m not verbose in this podcast. I spoke to Jon at length.
Andrew Hutchison: Okay.
Brad Serhan: He, he just gave in after, gave up after a while. No, I just, he told me there was the, pre loved, if that’s the right term. okay. And he, he kindly loaned it to me. and the only reason I’m, trying that is that I’ve had Gary Morrison’s wonderful, pure audio amps and loved his amp and still love his amps. but sadly, Gary’s, passed away and dear, dear man. and Jon’s amps is a joy to listen to, but I did listen to, but it’s also, I, designed a couple of pairs of speakers using his ampenne just the past six months.
Andrew Hutchison: Okay.
Brad Serhan: So it’s been a great designers tool, if you like. Perhaps I’m a tool. M mentioning it because. But anyway, it’s, it is. It is gobsmackingly good.
Andrew Hutchison: Yeah. I mean, I have heard it, but not, but not properly because I think.
Brad Serhan: Well, we were lucky enough to have.
Andrew Hutchison: It in a fire truck is not really.
Brad Serhan: We were lucky enough last year, the Melbourne steering Melbourne show, to share. Well, we were in two. There were two rooms. Jon was in two rooms. He was straddling both rooms. And he, we had, his pre power combination, with our, speakers. So we got to listen to it firsthand. So both Morris, myself, and Les Davis as well, we were just
01:20:00
Brad Serhan: gobsmacked at the quality of it. So, yeah, anyway, that’s a little bit hometown bias, but, Yeah, he wonderful.
Andrew Hutchison: Yeah, well, I mean, I’d probably buy it at that money based on the, just the level of, high level of engineering that’s gone into it. So involved.
Jon says he’s selling his amplifiers direct at wholesale prices
So, does that mean, Jon, that, that very sharp pricing that you offer these, these two pieces for means you’re selling them direct, primarily, does it? Or is,
Jon De Sensi: Yeah, yeah, so I’m essentially selling them direct, at wholesale prices, essentially, because I just want, you know, Australians, to have access to this, you know, locally made and I think, obviously biased, you know, excellent equipment. so my issue is like, nine times out of ten people that come into our showroom, yeah, walk out with amps or something.
Andrew Hutchison: Yes.
Jon De Sensi: M it’s just getting those bodies through. I have tried a lot of retailers, but, there’s a lot of issues with retailers in Australia. most of them import their own gear and have their own vested interests. our brand isn’t that well known, which is justifiable. And so there’s a lot of retailers that just want brand names that people are going to knock their doors down to come and buy. so I’m battling all of those issues.
Andrew Hutchison: Podcast in itself, the, yes, it is. Series of podcasts is the difficulties of, do you make your product a little bit more expensive? M because you’re effectively subcontracting out the retailing of it rather than doing it yourself and getting the advantages of that as far as it’s, having it sit in front of more people. But then you walk into your average, you know, professional good retailer these days, and there is so many products in there, you know, you, you got to work out how does your own stand out. And, And, I don’t know, that’s it. I don’t even want to, I don’t want to go there. There’s, it’s a, ah, many, many thoughts. And I’d have to, I’d have to, I’d have to take some notes for myself just to remember. It’s just such a complicated puzzle. It is, it is easier to sell it yourself, Jon, as you know, you just offer them for sale, do your own demos. But then the problem is, do people, you know, you’re missing 95% of the buying public straight away. That’s the, that’s the catch. That’s as far as. Because they’re not walking into your showroom, they’re walking into, you know, the, Well, you know, like I said, 95% of HiFi traffic is walking, of course, into a, into a HiFi showroom where they’re not talking about your product. I guess that’s why we’ve got you here today. for me, though, it’s a bit more selfish than that. It’s just, I just think it’s the most impressive Australia made HiFi product ever. Bold claim. But, and Brad, you know, don’t take that personally. and I don’t think, and I say that, no, because it’s the best sounding amplifier that’s ever been made. It’s just because it may well be, but it’s the most complete product. the fact.
Brad Serhan: Yeah, that’s a good way of putting.
Andrew Hutchison: All of those other things. Right. There’s three aspects to an amplifier, I reckon. It’s the way it sounds, is the way how well it’s made and how reliable it is. But then it’s how pretty it looks. And to get all three right, I think is incredibly hard. And you’ve done a fantastic job of that, Jon.
Brad Serhan: Well Jon. Jon straddles all three or four of those. All four. So.
Jon uses analog or pencil to scribe phono drawings
Andrew Hutchison: Well industrial design, Jon, was your own work in Covid time. Or have you got a mate who’s a guru at drawing lines on a piece of paper or something?
Jon De Sensi: Well I’m good at drawing. Drawing lines with a pencil.
Brad Serhan: Analog mate. Very analog of you.
Jon De Sensi: That’s good. Yeah. Yeah I’m still an analog fan. So we So we did that. But then You know, my. My very good friend now who approached me about the remote control initially and wanted to buy my equipment but couldn’t afford to. He’s the machinist. The CNC machinist. Well he. He’s a cad master so he drew.
Andrew Hutchison: It all up on. Cad master.
Jon De Sensi: Exactly.
Brad Serhan: It sort of reminds me the story. Sorry, it doesn’t remind me the story. Well sort of, not quite, but it sort of reminds me the bloke that sort of liked the rods and razor so much that he bought the company. And your. Your your mate who’s who I do know he sort of approached you about you know getting. Getting Doing the chassis for you. Sort of since got himself an amplifier very cleverly. I love it. It’s a great story. And the fact that you use analog or pencil to scribe initially the drawings draws me onto the word analog in terms of your phono.
01:25:00
Brad Serhan: preamp.
Jon De Sensi: Yeah.
Brad Serhan: I should not only let Andrew do that.
Jon De Sensi: So
Brad Serhan: I’ll hand it back to Andrew.
Andrew Hutchison: Well yeah. Well all I’m going to do is hand it back to me and we’ll have a quick break and we’ll come back and wrap up with discussion of both Jon’s history with music lab and onwards which we’ll cover briefly. And the phono stuff indeed. And then on that will. That will be the Jon de Senzi story for this round. But I think there’s a very good chance we’ll have Jon back at some future show to discuss a couple of things that we simply won’t have time to cover today. But Without any further ado we’ll nick off quick ad break and we’ll be back very shortly. Thanks guys. Hey, thank you for listening to the non audiophile podcast. It’s very much appreciated. We’d love your feedback. like follow comment, share all of that sort of stuff. Certainly. Comments on YouTube. We’re on YouTube. Fire away. Tell us what you think and we’ll. We may even answer you back. So yeah, thanks again for listening. this was the ad break. Back to the show.
Jon Desenzi from OAD Ultrafidelity talks about local manufacturing
Hi folks. Folks, Not An Audiophile podcast. Today has been an incredible tale of local manufacturing at a very high level from Jon Desenzi from OAD Ultrafidelity. And of course Brad is here as well from Sir Hannah Swift, giving us a hand and asking some probing questions. Jon, we all need to go. Life is short, we need to move on. But the listeners are thinking this particularly. But can we briefly talk about your music lab, just how that piece of the puzzle fits together and then, and just touch on your phono stage that Brad mentioned earlier.
Jon De Sensi: Right. well I guess music labs was my first foray into you know, manufacturing audiophile quality products in Australia. and like I said, we started with a real bang. Probably the best product, or certainly one of the best products I’ve ever made which was the music labs DAC, which was way, way ahead of what most people were doing at the time. just in a comparative point of view. and it probably would still be around today. It’s just that at the time in the nineties, the majority of all of my sort of distributors were actually in Asia.
Andrew Hutchison: Okay.
Jon De Sensi: And then we have the asian financial crisis.
Brad Serhan: 97 was that 97?
Jon De Sensi: 97. They all literally went under because they were all being funded by the banks.
Andrew Hutchison: Yeah.
Jon De Sensi: And they all wanted, and the banks wanted their money back and so they all folded and, and that meant m, you know, I had to start again. And, and it was also about the time where home theater was starting to gather a lot of traction in, in the audio world and people were more interested in multi channel lamps and.
Andrew Hutchison: Well because DVD just kicked off.
Jon De Sensi: Yeah, that’s, yeah. And so I thought I had another business opportunity and thought maybe this, you know, this, this has run its course. And and so we you know, we just let the company you know, drift and close down. Event.
Brad Serhan: Put into stasis. Jon. Put it into stasis.
Jon De Sensi: Yeah.
Brad Serhan: Sci-fi terms. Yeah.
Jon De Sensi: Yeah. So then we started Oid.
Andrew Hutchison: Yeah.
Jon De Sensi: OId was not initially going to be initially not going to be electronic, you know, manufacturing of amplifiers. It was going to be open baffle speakers, which is also a big passion of mine. And that’s in fact that’s what the OAD stance stands for, originally anyway, open audio designs to do with open baffles. But that became being a perfectionist. That became a very expensive sort of way to start up again. because of the way I wanted to do it About 15 years ago. And so we then just went back to doing Electronics first and then worked out a better way of doing the Speakers later on which weren’t so expensive, to manufacture.
Andrew Hutchison: Well actually, I mean open baffle surely the easiest or simplest or least expensive loudspeaker to manufacture in a way. But you had something exotic in mind as far as the baffle. Is that.
Jon De Sensi: Is that right? I did. I did. Yeah. Yeah. If I thought about what I’m doing now, which is exactly what you said, it’s the easiest, the most simple way of doing it. If I had done that I would have started with the speakers.
Andrew Hutchison: Yeah.
Jon De Sensi: I was looking at a curved front panel and I was looking at a non rectangular front panel and I don’t know what I was thinking.
Andrew Hutchison: Well you were trying to make it hard.
Jon De Sensi: That’s right. Well I thought that there were benefits and there. Then there are benefits doing it that way.
Andrew Hutchison: Yeah.
Brad Serhan: You’ve read Olson’s book. That’s what you’ve done. The spherical way.
Andrew Hutchison: No doubt.
Jon De Sensi: That’s right. That’s right. So And we. You know we. We contacted a lot of companies
01:30:00
Jon De Sensi: and got some CNC work and you know it wasn’t. Wasn’t pretty when we saw the prices. No.
Andrew Hutchison: No.
Jon De Sensi: And so we treated it back to electronic amplification manufacturing until we worked out The simple way that everyone else does it.
Andrew Hutchison: Yeah. Yeah. Which works.
Andrew Hutchison: One thing As open baffle speakers go yours sounds Startlingly good. And
Brad Serhan: Yeah.
Andrew Hutchison: You seem to have gotten most of the benefits of open baffle and not too many of the. Of the negatives of that Design arrangement.
Your phono preamp is very much an analog amplifier
Moving sideways To the phono preamp you’ve got. Because
Jon De Sensi: Yeah.
Andrew Hutchison: Just. Just a quick summary of what it is just as. Because it obviously fills out the range and it. I mean I guess it’s important to note that your amplifier, your pre power combo is very much an analog amplifier.
Jon De Sensi: Yeah.
Andrew Hutchison: And so to keep that to actually have an analog system you would need a turntable or a tape deck I guess. But Turntables probably easier to buy media for. So what What’s interesting about your phono stage?
Jon De Sensi: Yeah. So the phono stage Was always Going to happen but I didn’t know exactly how it was going to happen. And Before I thought too much about it I was m actually contacted by Warwick Fremantle who’s a major ah. Distributor down here in Melbourne of ah. Very fine. You know, gear from, from overseas. I’ve known Warwick for about 30 odd years and he asked me to make something that was sub $3,000 that was kind of world class.
Andrew Hutchison: Yeah.
Jon De Sensi: and, and so, we embarked on that path of achieving it. Luckily, Warwick brings in some of the best analog equipment. so we had access to $100,000 tech gas with top of the range lyra cartridge. probably a little bit of an overkill for a sub $3,000 product.
Andrew Hutchison: possibly still, you know.
Jon De Sensi: and yeah, so we ended up, you know, designing something that used three world class op amps. One, that’s specifically made for moving coil, which does most of the gain. and the, and then we wrap an RIAA around that, which is a partly passive, partly feedback, sort of, arrangement. yeah. and you know, it’s, it’s probably. I mean, and also because we were making these high quality CNC, all CNC paneled m. chassis for the preamp and power amp, we decided that the we did the same thing with, with the phono, and you know, which is probably wasn’t a great idea for a sub $3,000 product because it looks more like a $15,000 product. a lot of money. Well, that’s the thing. We haven’t put the price up in eight years that we’ve been manufacturing it. And we probably should because my costs have gone up.
Andrew Hutchison: I think that might have gone up.
Jon De Sensi: Yeah. It has gone up quite a lot and to date, it is still my best selling product. So we, we do actually sell quite a lot in Australia and we sell quite a lot overseas. so we’ve got a Singapore distributor, I’ve got an indian distributor who’s doing really well. Yep. I’ve got a swiss distributor.
Andrew Hutchison: Wow.
Jon De Sensi: Distributing it, you know, over there. Yeah. So, it’s, it’s a, it’s. Look, it’s, it’s a great little product. It does. It’s ultra low noise. very few phono amplifiers will have an 80 decibels setting. So this thing you can go up in five decibels steps from 40 or 60 decibels, up to 80 decibels. it literally has a wide range of lOADing resistors, that you can switch in and out, to suit literally any cartridge on the, on, on the planet.
Andrew Hutchison: Specifically, I’m guessing moving coil though.
Jon De Sensi: Oh, no, it’s moving coil and moving magnet.
Andrew Hutchison: Oh, is it really? Does both? Okay.
Jon De Sensi: Yeah. Well, yeah. So it has a 40 decibels, 60 decibels, switch where you can. You know if it’s a standard moving magnet, you can go to 40 db step up from there if you want. Yeah. Yeah. So. And it has input and has a range of three input capacitances. I mean you could use them on moving coil, but they’re more suitable for moving magnet, for matching.
Andrew Hutchison: Yeah.
Brad Serhan: That’s flexibility.
Andrew Hutchison: So it’ll match to any well like you say you said it in any cartridge, moving magnet or moving coil on the planet, you can set it up to match perfectly.
Do you have suggested settings for particular cartridges, models of cartridge
Do you have some kind of just. This is not really particularly technical question, but do you have some kind of chart I. That You know,
01:35:00
suggested settings for particular cartridges, models of cartridge? Is that something. Do you get feedback from clients or something on that? Or like where does someone start? I guess is other than looking up the manufacturer of the cartridges suggestions? which I guess is a good place to start. But Do you have any marks?
Jon De Sensi: That’s a very good question. Very very good question, Andrew. there are just so many different models that we, we don’t provide a chart. But I actually am in the process of Like You almost finished building a chart where someone can look at the data that came with their particular cartridge. And if they know how many micro volts or millivolts their cartridge is putting out, then it’ll give you the optimum setting so that you can get like a you know, fairly similar to a cd sort of output. You know, 2 volts. Rm’s.
Andrew Hutchison: Yeah. Okay. Yep.
Jon De Sensi: but we do in our manual we do state that you know that we’re happy to take phone calls. In fact we encourage people to take. To call us to find out you know, what setting they require for their cartridge. So we do, I do help people out, you know, almost sort of every fortnight, I would suspect.
Andrew Hutchison: It’s an interesting thing. So you can you answer the phone?
Jon De Sensi: I answer the phone. I answer emails. Yep. And give them that feedback and give them the settings? Yeah. Absolutely.
Andrew Hutchison: Old school levels of service right there.
Jon Senad thanks Andrew Hutzi for interviewing him on this podcast
Okay. Well look Jon, thank you so much for coming on today. it has been incredibly interesting. I’ve learned a hell of a lot and I’m gonna guess that the audience has as well. Brad hasn’t because he knew it all already. But he’s done a nice job of pretending. so I appreciate that. So yeah, look, thank you Jon. Thank you so much. Good luck with it. And we will you can supply us some information, photos and what have you, and we’ll put them up on the webpage for this podcast so that people can easily click through and find a more information about your products and and the finer details that we haven’t, we haven’t covered today due to lack of time. Although we’ve managed to make this the longest podcast ever. so, but it’s also been possibly the most interesting, I mean I shouldn’t say that all the other guests like, oh, but it’s tremendous. Yeah, but, but I mean, you know.
Brad Serhan: Give it our short term memory loss.
Andrew Hutchison: Well that’s the thing, it doesn’t matter. Yeah, that’s right. So no, it’s just so interesting and clearly very much cutting edge. it’s always slightly odd that someone goes to so much trouble to build an exceptionally engineered amplifier. And ultimately it’s for listening to music, not saving someone’s life or whatever, which I’m not sure what I mean by that, except I do remember once, just to clarify that point, I went to, I did a tour of names facility in Salisbury in the UK. And it was, it was just all these people in white coats. There’s a hundred people there or something, walking around in white coats, just bending the laws of physics, all for the sake of amplifiers and cd players. And I’m just like, if you could just put this effort into curing cancer, it would you know, be, make the world a better place. But but you know, that’s, I might edit that out actually. It’s sort of, I don’t want to, I don’t want to demean your effort, Jon, and I’m not trying to suggest you move into medical, electronics or what have you.
Brad Serhan: And you think about it, Jon, when you listed one of Jon’s amps, or.
Andrew Hutchison: Any of Jon’s, well, it’s going to improve your health, tends to relax.
Brad Serhan: So it’s, I think it’s a health, there’s some sort of health benefits.
Andrew Hutchison: And speaking of medical electronics, is that what, is that what Peter’s business? Someone told me once that me stood for medical electronics.
Brad Serhan: I thought it was modular. I think it’s modular.
Andrew Hutchison: Yeah. Yeah, that’s, but I have to check with you. That’s right. That, that’s it. Yes. As the person who told me that was an idiot, like, you know, vast majority of people are, so I shouldn’t, I think I might edit that out as well. I might do an alternate ending to this show.
Brad Serhan: You’re not a message rap, are you mate?
Jon De Sensi: No.
Brad Serhan: I didn’t think so.
Andrew Hutchison: Let’s read in this. And I can edit the last. Yeah, sorry. Keep going, Jon.
Jon De Sensi: That we don’t. We don’t have white lab coats.
Andrew Hutchison: No. No, you don’t. Okay.
Jon De Sensi: Yeah.
Brad Serhan: And I’ve heard that a lot of Jon’s best work is done.
Brad Serhan: No, I won’t go there. so. So the other thing is, it’s obviously, I think we’re setting it up. Or I’m setting up to say. Or Andrew mentioned earlier, we’d love to have you back, Jon. To discuss, other topics or maybe even one of our quick q and A’s and.
Jon De Sensi: Yeah, I’d love to.
Andrew Hutchison: Well, yes, at some point in the near future we will. We will stop offering history lessons, which I find very interesting and maybe not everyone does, and talk more about current issues in audio and what’s important and what’s not. So for that, we might indeed
01:40:00
Andrew Hutchison: get you back. And also you can fill in some gaps. some of the technical aspects of your product or any other aspect that you want to bring up. But thank you again Jon, to Senzi for coming on from OAD Ultrafidelity, Melbourne, manufacturers of exceptional quality amplifiers. And thank you again, Brad, for giving me a hand.
Brad Serhan: An honour and a pleasure, mate.
Andrew Hutchison: No worries. I’m Andrew Hutchison and this is, Not An Audiophile -The Podcast. Over and out for another, week. And we’ll be back soon. Bye, everybody.
01:40:27