Introduction:
“The engineer responsible for the design of the 1543 DAC is Scott Berry. Scott is an electrical engineer who worked for many years in R&D and manufacturing for Tektronix and Xerox on the West Coast of the USA. Scott’s experience was in electrical engineering R&D work in high technology industries, but not in the audio sector. However, Scott has always made his own audio equipment and concentrated on DACs because “I have always been a vinyl junkie and I just did not like the sound from digital sources“
Scott believes the future of audio will be computer based, and that is how Computer Audio Design started. “Not really having a history in audio development meant that the 1543 DAC took an original approach – different materials and ideas which I feel give different results.”
The 1543 DAC has been Scott’s passion for many years, and each unit is handmade using only the highest quality parts custom built to Scott’s specifications. Ninety percent of the parts in the 1543 DAC are manufactured in the UK by UK companies.
We encourage you to stop in for a listen at one of our dealers. It will be unlike anything you have heard before.”
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Hi Scott. First things first ¬ are you a DAC chip maker and if so are your chips made to your specification i.e. proprietary – or do you buy third-party off the shelf so to speak?
I use third-party / off the shelf New Old Stock DAC Chips. The Computer Audio Design 1543 DAC uses, well TDA1543/N2 DAC Chips – 16 of them actually.
Is microphony, (currently a big issue in the domestic audio world) a fact, or merely conjecture – or perhaps a bit of both?
I’m a big believer in “microphonics” reducing sound quality. In fact it’s the main reason for the case material of the 1543 DAC. The entire case is made from laser cut 10mm thick acrylic. During prototype work I made a similar case from aluminium. I put the exact same parts in both cases and the difference in sound quality was amazing. Acrylic has a resonant frequency different from aluminium and I find that the high frequency dampening effects of acrylic are superior to more traditional materials. There is also the fact that acrylic is completely non-magnetic – but that’s a different issue.
The 1534 DAC uses four hockey puck sized feet. These feet are made from a very soft polymer that forms a honeycomb design. I get a lot of comments about the feet. I tried a lot of different materials and designs…
To my ears these polymer feet were vastly better at damping out vibration than anything else I could find.
The PCB that contains the TDA5143 DAC chips is also isolated. I found that the DAC chips were very susceptible to vibration, or “microphonics”.
On the assumption that the primary objective of your designs are that it should neither add nor detract from the original signal, how can you determine that this goal is being achieved at the analogue stage? Or put differently, assuming that any analogue circuit must surely add it’s own sonic signature, however small, how is the extent of that signature determined?
I wish I had a tool to tell me that a modification improved or decreased sound quality. How easy that would that be! I think most audio measurements tell us very little. Some of the best sounding audio gear I have ever heard doesn’t measure all that well. Take a look at the specifications of the Nelson Pass First Watt SIT-1 mono block amplifiers. The distortion measurements are extremely poor! It’s only 10 watts! But if you ever get the opportunity to hear these amps with a good high efficiency speaker – wow!
The only way I have found to really improve my designs is by listening.
Back to the question, I try to put as few parts in the digital, analogue and power path as necessary. Many designers use operational amplifiers, transistors, transformers or tubes in the output stage of their DACs. These technologies all have their advantages and disadvantages. Over the years I have tried them all.
I like a current output DAC chip because I can have an output stage that doesn’t use any active parts. If someone wants a “tube” sound then use a tube preamp or amplifier. To my ears I find that I get a much more natural realistic sound using extremely high quality passive components for the output stage.
Currently, what is the limiting factor on the performance of a DAC? Is it the chip, the power supply or should I mind my own d**n business?
Without a doubt power supply. Everybody talks about DAC chips. The DAC chip is crucial for sure, and I’m personally a fan of R-2R non oversampling architecture. But the power supplies are at least as important as the DAC chip choice itself.
Now, a little bit of well-intentioned levity if I may. If Computer Audio Design were a automotive company, then which automotive company would you choose to be?
Lotus. Have you ever seen a grey Evora GTE ?
Yes, and I agree. Interesting choice. Most other audio designers I’ve interviewed replied Porsche. And so ……. given the apparent commercial failure of DVD-A and the less than stellar success of SACD, is their situation a sonic tragedy for the end user and if so, why?
I don’t believe it’s cost effective to build a CD/SACD/DVD-A player. So much of the cost of these players is the transport. Then there is the vibration that the transport creates ….
You can download DVD-A quality or better everywhere now days. SACD/DSD is not so popular but it’s still available for download. My very limited experience with SACD/DSD is that it can be seriously good and so I think that it’s a real shame it never caught on. I believe it’s huge in Japan though…
From your view atop the digital mountain, is there life left in the venerable Red Book CD format – or is it dying?
The reason I got into digital is because I never liked it. In my opinion the problem with Red Book digital sound is not the format – it has been the execution of the playback.
44.1KHz/16bit is far better than most people realize. I have no issues with the “Red Book CD Format” of 44.1Khz/16 bit. I would much rather have a well recorded and mastered album at Red Book then a 192Khz/ 24 bit highly compressed “pop” album.
So yes, there is definitely life left in Red Book. In my opinion there are a lot of people out there with massive CD collections that have probably never really heard how good they can sound. However, they need to copy them onto a hard drive and play them using a computer through a good DAC.
Do you believe that DACs in general and yours in particular benefit sonically from isolation systems?
Mechanical isolation is extremely important. I have put great effort into keeping vibration from reaching the components inside the 1543 DAC. Most people think about airborne and floor “foot stomp” isolation. These are the more obvious areas and a lot of people put a lot of work into minimizing these issues. But I’m also interested in high frequency vibration through cables.
You have your speaker cables connected to your speakers and your amplifier. The speaker connectors on your amplifier are typically soldered directly to the PCB board. That speaker cable is full of high frequency energy coming from the speaker. Vertexaq have some excellent white papers on the subject – I recommended reading them.
Thank you for the recommendation. Now then – how do you overcome the problem (if any) of dealers being reluctant to make a substantial capital investment in your products because of the industry’s contraction?
I really don’t have this issue.
But …?
Hmm. Okay … my biggest issue is trying to get dealers to even contemplate Computer Audio. It’s a very difficult task. It’s not the sound quality – they are more than happy with that. Someone started a rumour that Computer Audio was a “plug and play” technology. It’s not.
I sense you’ve more to say on this. Am I correct?
Yes. Streamers are beginning to move dealers away from CD players and into a kind of “black box” computer audio. This is great as it’s helping many dealers stay in business. However, computer based DACs are the next level of complexity – essentially because of the choice of hardware (PC / Mac) and software (literally dozens). Choices can be exciting – but a lot of work. I believe the work pays off and gives a much better sound quality , but this is my biggest challenge with dealers.
Frustrated but not bitter – right?
Correct.
Okay. Now back to technology. Do you have firm views on balanced inputs and outputs. What’s led you to those conclusions?
I think for home audio the extra electronics necessary for balanced outputs can sometimes do more harm than good. But I don’t have any firm views – both can be done very well if the design is good.
Who’s driving the industry today Scott, the music publishers or the hardware makers?
I really don’t know but here is my guess: The days of sitting down and listening to an entire album on a high quality two channel system seems to not be very popular with the “younger generation” (under 35?). Many of the iPod generation have never heard a good audio system.
The fact the vinyl sales have recently gone through the roof does show that when they hear quality – they like it and they buy it. These people now understand that maybe MP3 really isn’t that good. I think maybe both the hi-fi industry and the music publishers are a bit confused as to what to do at the moment.
In terms of sonic performance, have transport mechanisms gone about as far as they can?
Definitely. The cost for a good transport mechanism is massive. Why spend the money when a solid state hard drive with no moving parts has a price that is plummeting daily?
Okay, thanks. Moving on – digital room correction is a hot topic in some quarters. Any thoughts on the viability of the technique?
I don’t know enough about this to comment.
Fair enough. So in your view, what are the current limitations re approaching 100% accurate voice and music reproduction in the home?
100% accurate? I really don’t even know where to start! I think that’s too complex a question for me to answer. The simple answer is we can’t get even close to recreating a live performance in our living room. So go out and hear more live music and support the artists.
Do you attend live music performances?
Yes, I live in London so as much as possible!
Looking back on it, do you think the Linn/Naim flat-earth evangelists turned off more potential entrants into the upmarket audio world than they ever converted?
My first Hi-Fi purchase was a Nakamichi 480 cassette deck. I was about 16 or so. My second was the original Naim Nait, which my friend still uses to this day. I loved Naim for many many years and spent a lot of cash on it. I think the older Naim converted tons of people to “upmarket” audio.
Thank you. Your response is for me particularly illuminating. Frankly I’d not previously view NAIM as a converting force. But yes, I agree, So, moving on …what’s your business philosophy Scott?
Make a device that does one specific thing and does it very very well.
And?
And have faith that a good product will sell.
Nicely unambiguous. Thank you. And your personal philosophy?
I don’t like doing the same thing everyone else is doing. I usually do something “outside the box”. Also I’m a “bit” obsessive – if I get involved in something I want to do it at the highest level possible. I’m not talking just about hi-fi here. Everything I do – bicycles, motorbikes, coffee, wine, beer, food will be off the beaten track and the best I can possibly afford. Drives my wife nuts.
Okay Scott – it’s Desert Island digital time. Given you can choose just eight albums, what would they be?
Jim White: ‘Transnormal Skiperoo’
Cowboy Junkies: ‘Studio’
Beth Rowley: ‘Little Dreamer’
Stevie Ray Vaughan: ‘The Sky is Crying’
Steven Stills: ‘Stills Alone’
Oscar Peterson: ‘Exclusively for My Friends’ (4 box set – is that cheating?)
Damian Rice: – ‘O’
Leonard Cohen: ‘Old Ideas’
And your one luxury on that desert island?
My hi-fi
Was Hendrix really the greatest rock guitarist of all time? If not, then who was/is?
No, Stevie Ray Vaughan!
Bach or Beethoven for piano composition – and why please?
I’m not really into either so sorry – I’ll have to pass.
Finally, any message you’d like to give the readers?
Trust your ears.
That’s it?
No, not quite. The idea that “I don’t have good ears” is ridiculous. All we are trying to do is recreate music in our homes. If you can or cannot hear a difference that’s all that matters. Audio is not a test that you pass/fail. Trust in yourself and enjoy!
Anything else?
Oh, and please support small UK manufacturers.
Thanks’ Scott This has been both a pleasure and a privilege
Part #2 will follow in November 2015 and part #3 in mid 2016
