Which is most important for great two-channel, Pre-amp or Dac ?

Discussion in 'Archived Threads 2001-2004' started by John Tompkins, Apr 9, 2002.

  1. John Tompkins

    John Tompkins Supporting Actor

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    I was thinking about what a stereo pre-amp should do, some people say it should do nothing but control the volume. My question then would be why do people pay 2,000~and up for good stereo pre-amps? do they want the pre-amp to CHANGE the sound.

    The second part of my question is what would be more important for great 2 channel sound, a great dac or stereo pre-amp ? what would change the sound more. My thinking is that the pre-amp will contribute more but who knows.

    If you had the choice of a great seperate dac hooked up to a source with volume control or using a ht processor with bypass for volume control or getting a great stereo pre-amp what would be your choice and why ? thanks
     
  2. John Morris

    John Morris Guest

     
  3. Andrew Pratt

    Andrew Pratt Producer

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    In an ideal world you'd have a great DAC being feed by a great transport. This in turn would be passed on to a volume control that wouldn't add or detract from the sound at all. Now here's where it gets fun, if the line out's from the DAC are strong enough to drive your amp to levels that are loud enough for your listening preferences you do not need a pre amp but can get away with a simple passive volume control since you don't require any gain. Its a lot easier and cheaper to make a passive pre amp sound clean then it is to make a pre amp with gain sound clean which is why high quality pre amp's are expensive. Almost all volume controls add noise to some degree with the expensive units adding the least (obviously). My suggestion is to see if your DAC provides you with enough gain and if it does try a Creek passive pre amp and see how good your system can sound.
     
  4. BruceD

    BruceD Screenwriter

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    I will pass-on another little tidbit of info, a source with volume control (like a CD player) most likely uses a digital volume control. This means every time you turn down the volume from max, you are subtracting bits of resolution in the output (reducing the quality).

    I don't think this is the way to go. I'd probably side with John and say one of the newest prepros with good DACs and an analog bypass ( 2-channel and 5.1) for music would be better.
     
  5. John Tompkins

    John Tompkins Supporting Actor

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    Good points from all thanks,

    It still leaves the question as to why you would buy an expensive stereo pre if you didnt want it to actually change the sound it seems. Like you'll say you can get either a passive volume control or use a processor with bypass for volume control if its clean. Bruce brings up a good point about volume controls on sources that control digitally.

    I didnt want to list the my equipment etc. because I didnt want to make it about my situation. But this is where I'm at right now, I have the lex mc-1 which fills all my HT and multichannel music needs. I couldnt ask for anything more in this arena. My amps/speakers/subs/sacd needs are all squared away as I now have all "my" dream equipment.

    Really all this leaves for me to concentrate on is 2 channel stereo. The options are use my sacd player as a transport and hook it up to either a great dac going through the zone 2 on the mc-1 which bypasses all a/d d/a so I would be using lex just as a volume control for two channel. Or get a stereo pre-amp and add another cd player with a great dac built in (adcom gcd750 or similar) for non sacd two channel. What do you'll think ?
     
  6. Ricky T

    Ricky T Supporting Actor

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    Nice discussion. preamp and dac, seems like the next (and probably not the final) frontier for HT/Lexicon/upgrade freaks like John and I [​IMG] From my experience, one can discern slight differences between various dacs, but perhaps less than what some people say/think. I have yet to play the preamp game extensively, but believe in the shortest signal paths; even a passive volume or an Acurus DIA approach. Can someone explain how a tube preamp alters the incoming signal differently from a solid state preamp?
    On the variable volume control (connecting cdp/dac straight to power amp), what if the cd player had a motorized volume control on the front panel (and remote control) for it's variable analog outputs?
     
  7. Philip Hamm

    Philip Hamm Lead Actor

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  8. Larry B

    Larry B Screenwriter

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    John:

    Phil beat me to it, as my answer would be exactly the same as his.

    Two points to bear in mind:

    1. A system is only as good as it's weakest link.

    2. An analogue pass-through in a preamp processor avoids the A-to-D and D-to-A conversions, but the unit is still functioning as a preamp.

    In my admittedly elitist opinion, most preamp processors, even many of the more costly ones, are at best medicore for music. If music is of paramount importance to you, I strongly urge you to consider a good stereo preamp.

    Larry
     
  9. Saurav

    Saurav Cinematographer

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  10. BruceD

    BruceD Screenwriter

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    Case in point; I use a SS stereo preamp in my system that has a "direct" L&R input/output pair without any capacitors at all in the circuit, a Parasound 1100D.

    With this setup I use the DACs in my CD player and feed the CD's L&R analog outputs to the "direct" L&R analog input of the 1100D stereo preamp and then out to the amps for the L&R mains.

    My processor's L&R main outputs feed an "AUX" L&R input on the 1100D stereo preamp for HT use.

    As you can see I've configured my system for 90/10 (music/HT).
     
  11. Ricky T

    Ricky T Supporting Actor

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    Bruce,

    On the variable volume control (connecting cdp/dac straight to the power amps), if the cd player has a motorized volume control on the front panel for it's variable analog outputs (most cd players with variable outs only have this on the remote control), would you be losing bits?
     
  12. John Royster

    John Royster Screenwriter

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    I'd probably vote for the DAC. It is the single component crossing from digital to analog and what is really producing the waveform for your speakers, everything else down the line is there to amplify that signal and eventually move some air. [​IMG]
    For many years I did not have a pre-amp but simply ran the variable output from my CD player into an amp. sounded great to me. I'm curious about the talk of this attentuation being done digitally. I would think that would not be the case with this particular Adcom CD player as it boasts an all class A output stage and dual 166 Khz DACs? never know though.
     
  13. Frank_S

    Frank_S Supporting Actor

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    I use 2 different preamps in my system. I thought I could live with my Classe SSP-25 pre/pro and "Analog Bypass" feature but after borrowing a 2 channel tube preamp and hearing its capability, I ended up buying it. I use an EAR864 phono/line stage tube preamp. I listen to a lot of vinyl and the EAR just sounds smooth compared to the Classe.
    Don't get me wrong, the Classe sounded very nice but for 2 channel I must say the EAR864 brings it up to another level.
    I guess the tube linestage in the EAR just appeals to me more than the Classe solid-state line-stage.
    I would rather have 2 separate preamps in my system than try to spend megabucks on a processor to handle 2 channel and HT playback, just my opinion. I have yet to hear a HT processor knock my socks off in 2 channel. [​IMG]
     
  14. Tom Grooms

    Tom Grooms Second Unit

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  15. BruceD

    BruceD Screenwriter

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    Ricky T,

    Don't know the answer.

    You would have to look at the products manual, specs or marketing literature. Or open the CD enclosure and look at the volume control device (is it a resistor ladder?) and any controlling circuitry.
     
  16. Saurav

    Saurav Cinematographer

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    Ricky,

    According to what I've read, CD players are all over the map as far as volume controls go. Some do it in the digital domain, which by definition involves dropping the least significant bits. Some use digital control of an analog stage, so the up/down buttons on the remote control a stepped attenuator of some sort. And if you have a non-stepped dial on the CD player's front plate, I would guess that it's an analog control, using a motorized (or non-motorized, doesn't make a difference) potentiometer.
     
  17. ling_w

    ling_w Second Unit

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    If you get the Meridian 800 transport, 861 processor and DSP8000 speakers, you wouldn't have to worry about preamp at all the digital attenuation is done in 48 bits. So even if you turn down your volume down to 0, you will still have 24 bit resolution. And you keep the signal digital from the transport to the processor to the digital crossover in the speaker and then finally to the tailored for each driver DAC in the speaker. To boot, it will keep DVD-A/DVD-V digital all the way.
     
  18. BruceD

    BruceD Screenwriter

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    Don't know if the 8000 is any better, but I sure didn't like the sound of the 5000 and 6000 series of Meridian digital speakers.

    Besides, those systems are not in the real world as far as price goes (way too expensive in my book).

    To each his own though.
     
  19. John Tompkins

    John Tompkins Supporting Actor

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  20. Andrew Pratt

    Andrew Pratt Producer

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    from all that I've been told about CD players and pre amps the variable outs on virtually every CD player are fairly low quality and certinalty not as clean as those in even budget passive pre amps (creek etc)
     

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