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Is there a perfect preamp?

Paul's Posts — 07 August 2012

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Is there a perfect preamp?

Probably not and certainly since we can see far enough into the future to realize big sweeping changes are ahead for us when it comes to the control and preamplification of the music we really would be remiss in proclaiming that one thing or another is the perfect solution.

What we can do is suggest what’s most likely going to be the near-term solution for control.  I predict a transition period of products that will take two and a half courses: DACS with analog preamps inside, analog preamps with DACS inside and a slowly growing category of analog to digital converters.  It’ll be a while before the winners are chosen and there are good and bad points to both.

My guess is that DACS with analog volume controls and inputs will be the biggest winners for some time to come and here’s why: analog preamps with DACS inside don’t really hit the acceptance mark.  Most of us have an analog preamp and a DAC already and so the idea of selling our analog preamp to get enough funds to afford a new one because it has a DAC built inside doesn’t make a lot of sense for most people thinking about upgrading – yet as our analog sources dwindle the DAC with analog may make more sense.  An analog approach with digital inside might be a good idea for first time buyers who are more analog oriented: “I am an analog person but want a good sounding courtesy DAC built in”.

Future PS Audio DACS, for example, will more than likely have an analog input or two added to them and some type of clever switching circuitry that takes the analog volume control in and out of the circuit depending on what you’re listening to: digital volume control if you’re listening to digital and analog volume control if you’re listening to analog.  I also wouldn’t be surprised to see one of the analog inputs be a phono stage in manufacturer’s future DACS.  These take time to design and are probably several years out.  But they are coming.

Lastly I remember reading a review that Michael Fremer did on a digital phono stage that if memory serves correctly – he proclaimed it to be as good as any analog phono preamp he’s heard.  That’s quite something from Michael – a diehard analog vinylphobe if ever there was one.  So over time you’ll see a growing number on analog to digital converters and once they are accepted, the purely digital preamp can appear and make sense.

It’s an interesting and exciting future we have ahead of us.

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About Author

Paul McGowan

Paul McGowan is the CEO and co-founder of PS Audio Inc. a Boulder Colorado design and manufacturing company of high-end audio products and services. McGowan has been designing and building high-end products for nearly 40 years. Hobbies include skiing, music, hiking, artisan bread baking, kick boxing and cooking. He lives in Boulder Colorado with his wife Terri and his 4 sons.

(7) Readers Comments

  1. Phil Gan

    August 7, 2012 at 4:29 am

    That’d be “vinyl-phile”, not vinylphobe! phile – to love (from the Greek “philos”, as is philosophy – love of wisdom); phobe (phobos=Greek “to fear”, as in arachnophobia – fear of arachnids [spiders]) Cheers, Phil

  2. Arjen

    August 7, 2012 at 5:00 am

    Two questions:
    - If you use a digital volume control, why not postpone the DA-conversion to the power amp like Tact and Lyngdorf have done?
    - Is it wise to convert an analog source signal to digital to allow the use of a digital volume control before you go back to analog? Or would the extra AD and DA conversion do just as much or more harm than an analog volume control?
    Arjen

    • Tom Devey

      August 7, 2012 at 6:47 am

      If you are going digital, keeping the entire process digital until the last component would seem to make the most sense, as the analog portion is the one most susceptible to noise and having analog signals in cable runs wouldn’t make the best sense from this perspective. It would probably also simplify the DAC itself as there would presumably be only one type of digital signalling (USB 3.0 say) which would need to be converted than have a preamp accepting MP3, CD, Ethernet, and possibly others and then have to convert to analog at this stage.

  3. Soundminded

    August 7, 2012 at 5:16 am

    What is a “perfect preamplifier” and how do you know whether or not you already have one? A straight wire with gain (or loss)? Of all aspects of this industry which calls itself high end audio, I think the one area where it has made the least progress is in testing methodologies. I’ve been close to many research scientists and engineers most of my life. Much of what passes for research in this industry is really nothing more than tinkering. When a tinkerer tried everything he can think of and finds something he “likes” better than what he had before, it’s a breakthrough.All that’s needed is some sort of theoretical qualitative justification for it and a friendly review in a magazine.And that stands until the next time when it happens again exactly the same way.

    So how would you test a preamplifier? Testing preamp A against preamp B to see which you like better isn’t the right way. Preamp B has a high end rolloff or poor slewing that mitigates the shrill peak in the speaker or phono cartridge that preamp A doesn’t have and so you conclude preamp B is better. Wrong answer. Putting it on a test bench to find out its electrical characteristics doesn’t work either. The tests don’t simulate real world conditions, don’t tell you everything you need to know. Power amplifier #1 has a 5 Kohm impedance that loads down preamp A and it sounds terrible. Power amplifier B has a 250 Kohm impedance and suddenly preamp A sounds great.

    So what’s a valid test? Preamp A versus Preamp A shunted in a doulbe blind test wtih prescreened listeners on a wide variety of source material and many different power amplifiers. The test has to be performed at many different volume level settings so the input volume will have to be varied to keep the test within acceptable loudness limits (we don’t want to deafen the test subjects.) If they can’t hear a difference, likely neither can you. Further improvement will not be audible. And you may not like the way it sounds. Revealing flaws in other equipment instead of masking or mitigating them is part of its job. At least according to this definition of what it’s supposed to do. BTW, the test is indifferent to the technology. It doesn’t care whether it’s analog or digital, tube, discreet transistor, Mosfet, Bipolar disorder,IC op amp, silicon, germanium or geranium.

  4. bobk

    August 7, 2012 at 6:31 am

    Paul,
    I really enjoyed your comments this morning. I have not yet taken the plunge into streaming audio but plan to do so when you release the Silent Server later this year (combined with the PWD). The one area I’ve struggled with is what to do with my significant collection of SACD’s. Currently, I plan to keep my Ayre C5xe to continue to play them (unless I find a better solution), but then the sole purpose of my existing preamp would be only to play those discs, and losing out on the higher fidelity of the digital path for the bulk of my library. Adding an AI option to the PWD solves my problem.

    • August 7, 2012 at 7:50 am

      Thanks. SACD’s are a real thorn in everyone’s side – great stuff but hard to get it out right.

  5. jazzoid

    August 7, 2012 at 8:48 am

    While I do not disagree with where digital / preamps are headed, I will not take that approach for the foreseeable future. Here is why. Preamps and amps are relatively stable in terms of new ideas and improvements. That is why a 30 year old amp can sound great.

    DACs are really computers that are obsolete in 6 months,but not quite as annoying. I have your Perfect Wave DAC Mk 2 and it is excellent. No doubt next year’s version will be much better. I have gone through maybe 4 preamps in 25 years. I have gone through about 10 CD players and DACs in the same period. I have both a large CD and vinyl collection and will enjoy both. I will enjoy both into the future.

    I do not rapidly churn my system as others do. Combining analog and digital intimately is just not cost effective at the higher end of things. I plan on keeping them separate for a long time.

    By the way, I hate the touch screens and like real buttons.

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