I have owned a number of preamps, both active and passive. Ive finally settled on a passive from Placette. It is mercilessly accurate and transparent. It comes with a full money back guaranty if you dont like it.
http://www.placetteaudio.com/ |
It is my contention that if you have:
1. A source with low output impedance, most made today do
2. A power amp with a high input impedance, many do, especially tube amps
3. cables with low reactance that aren't too long from pre to power amp, I use 1/2 meter Cardas Neutral Reference
there is no way an active stage can do anything but degrade the signal.
I have used and I am using a passive preamp with wonderful results. Great dynamics, superb resolution, plenty of extension on both ends of the frequency spectrum, and I saved a bunch of money not having to buy an expensive preamp.
As suggested, buy a good used unit and try it. |
Eldartford, even though I was funnin..your answer shows great knowledge. I have therefore placed you name in my little book of people to come to for answers, you are a great asset to this site...and I'm not funnin this time!
Dave |
Sogood51...Sometimes, on this site, it's hard to tell the jokes from the serious comments! |
Eldartford, I was just funnin.
Dave |
Passive preamplification can:
- roll off the top end and the bottom end
- limit dynamics
- limit resolution, especially at low volumes
- limit gain
Now there are definite levels of passive preamps. And possibly the absolute best passive preamp that is matched 100% correctly to a given system may be better than an active preamp (maybe any active). But these passives are few and far between (I have yet to hear one). Passive preamps get better and better as the volume control is opened up more and more (as more signal flows through them). I went from passive preamplification to tube active preamplification and it was like a haze was lifted off of the music.
KF |
There is no way to "clean up" an analog signal by running it through a few stages of amplification. There were (are?) active devices like Carver's Phase Linear Autocorrelator which was a dynamic noise filter which "cleaned up" LP rumble and surface noise quite effectively, but I don't think that such circuitry is included in a preamp (other than the Phase Linear preamp).
In the digital domain, cleanup is possible to correct various digital parameters like timing.
However, a preamp can change the sound, and perhaps in a way that sounds good. Usually this is the result of harmonic distortion, which adds harmonics similar to those produced by musical instruments. For example, some violins produce a different harmonic signature than others when played in exactly the same way. The harmonics that are missing in the inferior instrument might be added in the preamp. However, IMHO, this sort of sound improvement should have been done by the recording engineer when the media was created. |
I'll have whatever Dave's having... |
Pace, Rhythm, And Tequila! |
Pmkalby, the signal is stored in the buffer, cleaned up and then released as a new signal full of PRAT, you didn't know that?
Dave |
It's up to you. I just just started using a Musical Fidelity 3.2 preamp after running the EVS attenuators for over a year. I found that I was missing a lot. The sound is much more open deep,and detailed.
Tim |
Timo-
I think you are correct that many preamps add "body" to music, and I'll always have a preamp since I have a system with many sources of varying output levels.
BUT how would a preamp change PRAT? I tend to believe PRAT is source dependent exclusively. If the device spinning flat stuff, whether read by laser or by stylus delivers a signal with good PRAT to the preamp, where exactly in the circuitry does the preamp alter this and how? |
I've heard some really good passive systems and some really unimpressive ones. Preampless(?) rigs require very carefull attention to system synergy. Going without a pre-amp is harder, but, can work very well indeed. |
There is no such thing as a completely neutral preamp. They all add and/or subtract something from the signal. If we assume that your amplifier has high enough sensitivity and high enough input impedance to be driven by a passive then that is the most accurate source period!! BUT, since digital needs help to sound good who in the hell wants to listen to an accurate portrayal of a digital source? My personal opinion is that the colorations of tube gear make the sound of digital more musical and listenable and yes I have compared countless solid state & tube units against passive control. If you want the most accurate portrayal of the recording go passive. If you want your system to sound more musical-more pleasant-more or less of whatever you want then choose your coloration generator(preamp)to satisfy your personal taste. I recommend TUBES. |
Tweakaudio.com manufactures two models of the Ultimate Attenuators for either tube or transistor amplifiers. They attach directly onto the amp RCA input jacks so no interconnect needed. Ric Schultz is the designer. Thirty day trial offered on these custom made pairs, with $350 list price. On my systems these allowed excellent sound upgrade for either tube or transistor amps. If you check the archived Audiogon comments from myself and other Ultimate Attenuator fans then you will surely be intrigued. You need a really enjoyable amp since you get to hear all it is doing for the first time. |
If you're willing to try a cheap experiment buy the Luminous Audio AXIOM passive pre for $125. It has only one set of inputs and one set of outputs. The Antique Soundlabs T1 DT I have sounded a bit muddy in comparison.
Tim will ask you to supply him with the output voltage and output impedance of your DAC or other source and the input impedance of your amp in order to configure a unit which will have the least matching problems.
An experiment like this will help you determine whether you need any preamp at all. Me? I prefer having a tube preamp because of what it adds.
Good luck! |
You would need to try your self..in your system. Two of the best systems at this site are at odds. Both use tube amps, one system has active pre..the other is a passive setup. Which is right and which is wrong? Opinions, opinions, opinions.
Dave |
Yep. I agree with the above. Passives give me a thin sound, totally lacking in body and especially dynamic range. |
Timo is right. I will always have a preamp in my system. |
Technically no; however, musically maybe. Some preamps, especially active ones add a sense of body and PRAT to the music that doesn't come from a direct connection to an amp. |
YES.
KF
Read my previous posts on preamps vs. no preamp if you want more elaboration. |
