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  1. #1
    Join Date
    Nov 2004
    Simi Valley, Ca

    To Preamp, or not to Preamp is the question

    Being a serious listener, I like the idea of having sonic PURITY of the actual recording coming through the speakers as undisturbed as possible. I am of the opinion that although preamps are wonderful in many ways, they also come with some unwanted baggage.
    A few downsides to preamps:
    1) they induce colorations of accentuated bass and/or highs.
    2) they contribute to the noise.
    3) There is added channel separation loss.

    The overwhelming offence (IMHO) is the first one - coloration - especially the preamps that have the "contour" or "loudness" feature. It's like having an equalizer to adjust the sound for the wrong reasons. (Tuning the sound to overcome the characteristics of a room is one thing - deviating from the original musical medium is another).

    The second offender is separation. When I use a preamp versus just direct into two mono blocks or into a dual channel amp, I notice a drastic difference in seperation. Sonic imaging and transparancy is markedly better. I find that even a quality preamp downgrades the music.

    Here's how I handled it ---> I DO NOT USE A PREAMP.

    I have a CD player that is piped directly into a a very quiet, but very powerful two channel power amp. The amp has separate left and right volume controls. (I have used two mono blocks as well with the same results).

    Of coarse, this is all per my individual taste, but I see the the setup as one of the best kept bargains around. A 200-250W QSC, BGW, Fender or Hafler amp on the used market is only $100 to $300. They're used at Churches for P.A. systems every Sunday and are not abused like some band instruments. Most importantly, they're made for professional musical reproduction.

    There is one drawback - these amps tend to come with a fan. Which means I have to stow it in a cabinet or closet, or (very worst case) have it in the next room. I regard it as a minor degree of effort for sake of sonic purity.

    Then again, I could be wrong.
    Anyone else running with a similar setup?
    Opinions, comments?

  2. #2
    Loving This kexodusc's Avatar
    Join Date
    Nov 2003
    Department of Heuristics and Research on Material Applications
    Yep, I have a few...I, too, use to run my CD player straight into power amps. But I've since abandoned that practise.
    First, I believe the pre-amp is the most overlooked component (next to room acoustics) in a good stereo system.
    While I agree there can be some advantages to plugging the line out directly into the amps, there's a problem with that...Those amps are built with accepting a signal straight from a source player in mind, the signal transfer can (and quite often does) suffer IMO. Why? I can only assume the components in the pre-amp stage are of better quality, or at least better design to amplify that signal without alteration or distortion.
    Second, the source player isn't usually designed to feed a signal straight to an amplifier. I've often heard from good sources (though I can't confirm this) that boosting the output signal via source player volume control often adds noise or distortion to the signal.

    Both of these add up to the need for a GOOD pre-amp stage. Good doesn't necessarily mean expensive.
    I've heard decent integrated and receivers perform better than some similarly priced pre-amps with brand names on the front. This is an exception rather than a rule IMO, but the pre-amp stage is there for a reason. Like anything in audio, there are diminishing returns.

    I always rank the pre-amp as being equally important to the amplifier for good sound, just behind speakers and room acoustics as the items having the most impact on total system performance.

  3. #3
    Suspended topspeed's Avatar
    Join Date
    Jun 2003
    While I understand the logic for plugging your source directly into the amp(s), for those of us that use multiple sources, switching the wires every time would be at best a complete pain in the keester and at worst damn near impossible if your rig is built into the wall like mine.

    As long as all of your source components have enough gain, I'd suggest a good passive preamp or at least one that has a Straightwire mode that bypasses any gain stages within the pre and also defeats any tone control. My old PS Audio 4.6 had that feature and I used it exclusively in passive mode. Also, for those audiophiles that are into vinyl, they are going to have to have some kind of gain stage inserted between the deck and the amps, no?

  4. #4
    Music Junkie E-Stat's Avatar
    Join Date
    Dec 2003
    Quote Originally Posted by Tunaoue
    Being a serious listener, I like the idea of having sonic PURITY of the actual recording coming through the speakers as undisturbed as possible. I am of the opinion that although preamps are wonderful in many ways, they also come with some unwanted baggage....Anyone else running with a similar setup?
    I use attenuators in lieu of a preamp in two of my systems with slightly different outcomes. Basically, there are five variables to be considered:

    1. Output impedance of high level source(s) be they CDP, tuner, etc.
    2. Output voltage of source
    3. Input impedance of amplifier
    4. Input sensitivity of amplifier
    5. Capacitance of interconnect cables

    Controlling two overall considerations:

    1. High frequency rolloff
    2. Dynamic presentation

    Ideally, one would have a source with high output voltage and low output impedance driving very low capacitance cables into a high sensitivity, high impedance amp. My main system is a good example.

    4 volt / 75 ohm output CDP-->20 pf cable-->10k attenuators-->80 pf cable-->1.8 volt sensitivity 137k ohm amp.

    The result is that I rarely run the attenuators beyond -18 db to fully drive the amps. Using the DACT calculator, the HF rolloff is nonexistent and dynamics are not audibly constricted. Not to mention better resolution and image width by not using the preamp (which I use only for my vinyl source where the gain is required).

    With my vintage garage system, however, the results are not as ideal. Without going into the particulars, I cannot get full gain out of my amplifier using attenuators. Using a preamp would solve that problem, but quite frankly I can drive the speakers to satisfying levels as is with higher resolution.

    I believe the key is understanding the variables and determining / selecting components that are a good match for use with attenuators.


  5. #5
    Silence of the spam Site Moderator Geoffcin's Avatar
    Join Date
    May 2003

    One of the reasons that I've kept my old Preamp is

    That is functions as a passive preamp. My CD player also has a high voltage output, so there's no need for added gain. I'm of the "shortest path is purest" mind. That being said, most modern preamps are very quite, and have seperation on a par with all other components.

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