Why is "no preamp" best?

[ModelCitizen]

ClibeB's post in another thread has me confused and I was hoping that I may get some input that would clear up my confusion.

The best preamp possible is no preamp at all.

You can have a hifi set up wihtout a pre-amp? I currently use a Transporter directly into a NAIM power amp. However I am under the impression that I am using the Transporter's built-in pre-amp. Is this not true? If it is true why should the pre-amp be better than than the NAIM pre-amp I used to use?
NAIM dealers tend to say that using another pre-amp (rather than a NAIM) can introduce "instability" (yup, I know... not too technical, but then NAIM dealers tend towards the wooly rather than the technical). Patrick Dixon has said on these forums that the pre-amp should block very high freuencies (out-of-hearing range one presumes) to work properly with a NAIM amp, otherwise "instability" is the result. I assume that if this is the case with NAIM it might well be the case with other power amp/pre-amp combos.
My experience is that not using a pre-amp with a Transporter "might" produce a harsher sound (not tested as testing is very hard to do in this case). I may well be entirely wrong about this though so please take this observation with a dose of salt.
MC

[95bcwh]

There is no universal truth in this hobby..there's no need to get confused over what others are saying.

Have you ever been to a restaurant ordering the most popular manu and found out that it taste absolutely crap to your tongue?

High end audio is not much different in this regards, trust your own ear. You may like a preamp, you may not, so now you find out that the transporter sound "harsher" without preamp, are you going to use a preamp, or are you going to get used to the harsh sound just become someone said that no preamp is the best? Who is that someone to tell you what's right for you?

[PhilNYC]

The theory for "no preamp is the best" is based on the idea that the less that is done to an audio signal, the better. And there's probably a lot of truth to that.

However, most amps out there today are designed expecting a certain voltage level coming to the input, and most digital sources out there either don't output an optimal voltage level to match the amp, or they have some kind of gain stage after the D-to-A process that is actually pretty much akin to doing exactly what a preamp does in terms of gain. The audiophile "traditionalist" will argue that having this preamp section as a separate box is a better idea, based on the whole reason for "separates" to begin with...dedicated power supplies to each section of the audio chain, better EM/RF isolation, vibration control, etc. In other words, if you believe in the value of separates, then a separate preamp makes sense if the amp is designed to receive a relatively high input voltage.

[Phil Leigh]

I'm sure CliveB will jump in here, but given the extremely tortuous path that the original sound has already gone through by the time it arrives in your house as a CD, whether or not you have a pre-amp in the mix is totally irrelevant. I mean - think about it for a moment - what exactly does anyone think they are trying to preserve? What we listen to (on any recorded media) is NOT fidelity - it's an artefact - like TV or looking at a painting/sculpture etc - it's a work of human creative art. The technology is unimportant.

I say this: if a pre-amp sounds best in your system then use one - if not, then don't.

[95bcwh]

Phil, with all due respect,

"less is done to an audio signal" does not necessarily traslate to "good sound".

Regards
barry

The theory for "no preamp is the best" is based on the idea that the less that is done to an audio signal, the better. And there's probably a lot of truth to that.

[kanoot]

I've always subscribed to the theory that if it sounds good to me, then it sounds good. If it sounds bad to me, it sounds bad. This way I keep the "signal" from going through too many paths.

[PhilNYC]

Phil, with all due respect,

"less is done to an audio signal" does not necessarily traslate to "good sound".

Regards
barry

Never said it did. Personally, I strongly prefer the use of a preamp in my system.

[ModelCitizen]

I agree with all of these posts, in that, what sounds good to the listener is best.
However, the original quote said that no pre-amp is best.
But, if the Transporter does not have a pre-amp how can it drive my power amp? It must have a pre-amp (but no pre-amp is good, according to CliveB).
And a follow on is... how on earth can I just unplug the Transporter from my power amp then plug in into my pre-amp and it sounds fine.... i.e it does not blow it up! The signals levels for a feed to a pre-amp and a power amp vary by a magnitude.... but I don't have to tell the Transporter what it's feeding, it just seems to know. How can that be?
MC

[Greg Erskine]

hi ModelCitizen,

The Transporter's unbalanced analogue output puts out 2Vrms which is enough to drive any of my amps without a pre-amp.

Historically, the job of a preamp was to boost the signal from phono or tape deck inputs up to the required voltage for an amp.
Also, some input signals needed filtering (RIAA??) so the preamp did that.

While we are talking about voltages it is worth remembering about DC voltage. To prevent DC voltage getting to the speakers we insert a DC blocking cap in the signal path. You'll will find your amp input probably has one, but also preamps will often have one (or more) as well. Some people don't like caps in the signal path so adding a pre-amp isn't desireable to them.

Next, you need to look at the input and output impedances of the devices in your system. If your amp is happy with the 100 ohm output impedance of the transporter and the transporter is happy with the input impedance of your amp (mine's 47K) then everything will work fine. If this is not the case, a preamp can be included in an attempt to isolate the transporter from the amp and hopefully supply the transporter with the ideal load and your amp with the ideal source.

I use a valve preamp, which actually is just a buffer because it has amplification of just less then one. It acts to isolate the transporter and amp, adds an extra DC blocking cap and adds some warmth (or is that distrortion?) to the sound. I find my preamp is a very minor improvement to the sound to my ears.

So, there are many issues and combinations, and that's why we all have different opinions.

regards
Greg

[empty99]

I agree with all of these posts, in that, what sounds good to the listener is best.
However, the original quote said that no pre-amp is best.
But, if the Transporter does not have a pre-amp how can it drive my power amp? It must have a pre-amp (but no pre-amp is good, according to CliveB).
And a follow on is... how on earth can I just unplug the Transporter from my power amp then plug in into my pre-amp and it sounds fine.... i.e it does not blow it up! The signals levels for a feed to a pre-amp and a power amp vary by a magnitude.... but I don't have to tell the Transporter what it's feeding, it just seems to know. How can that be?
MC

Except for the old LP/Phono sources, which are extremely low in level, requiring step-up preamp stages, most modern music sources, ie CD, DVD, Tuners and yes, even Ipods, provide higher output voltages (around 2V), enough to drive many amps into overload. How can you be sure? Just read the specs on many amps...1.5 or 2.0v input sensitivity for rated output, etc....
Your Transporter is of the same high output class, made even better by good power supply and output stages up to 3v and with built-in volume control, it qualify as a preamp, a very good one at that.
For most system, a simple 2 channel voltage potentiometer (pot) with low impedance is all one need nowaday to control the signal from your source to many mainstream amps (read the specs listed above just to be sure). A rule of thumb if you use this route:
1/ Use low capacitance cable and keep them as short as possible.
2/ Use high quality pots, such as Alps, Penny&Giles, TKD and those made to order fixed value clickers, ie DACT (nice, but expensive). There are huge aftermarkets for these since people find out how clean they can sound.
3/ Use brandname finished passive preamps (oops, by definitions these are NOT preamps, they are switcher/level reducer) such as Mod Squad (now McCormack), Placette, Django, Simaudio, Bent Audio, EVS and CIAudo etc...
4/ Keep your cables short!