preamp vs. no-preamp


Hi guys, I would like to know your opinions regarding the classic question (which also has been posted many times in this forum, I know, I know) whether or not a preamp is needed for a good (= musical sound). You see, if you can delete the preamp and connect the DAC into the poweramp, you can save lots of money, sometimes up to $ 15,000 for a Conrad-Johnson ART (this is off course an extreme example). The money you have spent on the preamp can be used for buying a better source or amplifier (mono's?). So theoretically if you don't have a preamplifier you can improve the sound reproduction by: deleting redundant audio circuitry and interconnect cables, upgrading the quality of you source, poweramplifier or speakers.
My personal experience is that without a preamplifier the sound is becoming thin and uninvolving, but I know there are audiophiles who don't have a preamp in their audio system.
dazzdax
Great thread. I am currently running my 9000ES through a pair of Rick Shultz attenuators. The amp. is a Anthem amp2 and Totem Forest speakers. I was looking at the matching anthem pre. or the Adcom 750. After I pay off some of the Cristmass bills.....
Tim
Gboren: You're looking at the subject too narrowly

Not all "preamps" are connected to devices that emit high level signals. There are such things as a phono system, which requires gain prior to being fed to an amplifier. Try running even a high output MM phono cartridge "wide open" into a power amp and see what you hear. Obviously, one needs a LOT of gain in this situation, regardless of the amplifier being used. As such, ANY attenuation of the signal would result in hearing "less than nothing".

As far as line level signals go, some sources simply don't output as much drive as an amplifier may require. This could be due to a weak signal being received from a distant broadcast, very quiet recording ( which applies to tapes, cd's, etc..) or simply due to the fact that the source component itself does not have enough gain in the output stage. As such, additional gain / further amplification may be required prior to feeding the signal into the amplifier to achieve the desired listening levels.

To top this off, some amps offer different levels of input sensitivity. While some amps may roar with as little as 750 millivolts ( .75 volts ) fed into them, others really do need at least 1.5 - 2.0 volts for full output. Since i have seen some sources that put out less than 1.5 volts when driven to capacity via loud recordings, this still may not be enough. For example, the Philips SACD 1000 maxes out at 1.6 volts output in SACD mode when a high level signal is fed into it. On music that does not "roar" and a quiet recording, it is quite possible that you might only have peaks of 500 millivolts to 1 volt available to drive your amp with. For some amps, this would just start to "tickle" them and not really be enough to get their "full fledged attention", hence a lack of volume and squashed dynamics.

All of the above situations would be highlighted even further if using long runs of lossy cable, suffered from signal loss due to poor loading ( impedance problems ), and / or using highly in-efficient speakers.

Having said all of that, i do agree that most of the problems associated with using a "passive" has to do with impedance mismatches and / or weak recordings that aren't strong enough to drive the gain stages of a source component to full output.

If one wanted to avoid such a situation, i'd look for a source ( tuner, DAC, CD Player, etc... ) that was capable of at least several ( 3 - 4 volts ) of output. This should be plenty to drive any amplifer / speaker combo to high listening levels. It would do this without pushing the gain stages of the source into compression, even with a quiet recording. The end result would be no need for a preamp, so long as you only had one line level source that you listened to or didn't mind swapping cables between multiple sources.

Those of us with phono systems, multiple sources and "thirsty" amps / speakers don't mind using an "active gain stage with user selectable inputs" : ) Sean
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Running my Wadia 860x into a VAC 70/70 MKiii didn't sound as good as using a VTL IT85 (basically a VTL 2.5) with NOS tubes (bugle boys, 7316). The Wadia direct was too bright! Using the pre sound better (full, rich), without sacrificing detail.
I am for with preamp.Flemke by the the adcom 750 is more
tansparent than krell ksl i used to have.I think very
people realize how good is this 750.
sorry to get sidetrack.I have tried theta cd,dac audio
alchemy,and heard wadia,and heard the accuphase $27,000
without preamp,they sound better with preamp,although
if, i dont have the money, i can live listening without
preamp, with this gear especially the accuphase Sacd.
I heard the conrad j ART this gave me the hair raising
experience.
As with everything else in this hobby, it's really about what kind of sound is "preferred" vs which sound is the "best". If you prefer the sound using a preamp, then thats the "best" sound for you. There is no ultimate sound that we will all agree on. It always amazes me that we hear that the goal of hi end is to pass the music from the source to the speakers without adding anything. Yet, if we line up 10 equally expensive components for comparison, each sounds different. Obviously, its not in the best interests of the manufacturers to have all amps sound the same, because our preferences vary so much as individuals. So they intentionally tweak their products for a particular sound that will appeal to a large enough audience, who then declare it to have the "best" sound. Best for them, but not for everyone.