The effects of a pre-amp and power-amp

[wilro15]

I have only ever owned integrated amplifiers or AV receivers so have never experienced the effect a pre and power has on a system when they are changed/upgraded. Obviously they have well defined roles: a pre controls the gain/volume and input selection while a power amplifies the signal and drives the speakers.

How does each affect the sound?

My guess is that the pre gives you the soundstage, separation of sounds, detail and overall tonal character. My other guess is the power amp gives you the thump, impact and dynamics. Am I right in that?

 

[james_LR90]

Not sure what the role is with an active pre but my pre amp is passive and is simply a gain control and does nothing to the sound and it is the quality of the components and circuit design which is responsible for soundstage depth etc. I have found that my pre / power combo is much better at soundstaging and painting a musical picture than my intergrated was. My amps combined with my speakers are just superb.

 

[abacus]

I have only ever owned integrated amplifiers or AV receivers so have never experienced the effect a pre and power has on a system when they are changed/upgraded. Obviously they have well defined roles: a pre controls the gain/volume and input selection while a power amplifies the signal and drives the speakers.

How does each affect the sound?

My guess is that the pre gives you the soundstage, separation of sounds, detail and overall tonal character. My other guess is the power amp gives you the thump, impact and dynamics. Am I right in that?

Your 1st paragraph is correct, however your 3rd paragraph is wrong.

Whether integrated or separate an amplifier is designed (Or should be) to reproduce exactly what is fed into it, at a level to drive the speakers. Nothing more nothing less.

Hope this helps

Bill

 

[wilro15]

Thats not the case in reality though. Every integrated amplifier I have had has sounded different. I would have to fallback on the cliches of warmer / brighter / smoother / detailed to describe it. What I wonder is, does this difference in presentation come from the "pre" or "power" part of an integrated - or both?

 

[Laurens_B]

Thats not the case in reality though. Every integrated amplifier I have had has sounded different. I would have to fallback on the cliches of warmer / brighter / smoother / detailed to describe it. What I wonder is, does this difference in presentation come from the "pre" or "power" part of an integrated - or both?

I think the terms you mentioned come from expectation bias. I have not succeeded in identifying them blind, though I was able to identify sighted.

 

[wilro15]

So all amplifiers sound the same? Come on...

 

[Laurens_B]

So all amplifiers sound the same? Come on...

Not saying all amplifiers, but the ones I tested, around the 1000 Euro mark, decently built, level matched and blind, I could not distinguish between them. Oh, and also could not distinguish between the integrated and AV receiver (around the same price tag). Then when investigating their frequency responses, they all appeared to be flat between 20Hz - 20kHz. It is also incredibly easy to build an amplifier with distortion levels far below ambient noise levels.

Just sharing my experience though, I am not pretending to wield the ultimate truth. You asked the question, I have asked the same question before, and these are my results.

 

[Vladimir]

So all amplifiers sound the same? Come on...

Far from it. Tube amps are all different, Naim seems to have its own sound theme, some amps with high intermodular distortion can sound shrill etc. However, all well made solid state amps with neutrality in mind do sound the same when not pushed to their extreme.

 

[davedotco]

So all amplifiers sound the same? Come on...

My thought is this, all amplifiers are set up differently in different ways and some encourage the user to have different expectations, or perhaps use higher volumes, only by a tiny amount, but that is enough.

Other amplifiers, 'classic' Naim for example set up their amplifiers to sound fast and exciting, lots of gain early in the circuit will do that, impressive initially but can be fatiguing in the wrong setup.

As always with hi-fi, different people react to these amplifier 'characteristics' in different ways but if the test is set up blind, with the levels carefully matched, many of the 'characteristics' are taken out of the equation, so it becomes much harder to tell the difference.