So, do all amplifiers sound the same?

No, Not IME.

We did this recently. 

There was not a consensus. 

Short answer, no. But, and it is a big but, they can most probably be made to sound subjectively very, very similar. So much so that it probably would take a trained ear to point out the differences. That is regardless of cost and power, as long as they are reasonably well engineered without obvious flaws such as hum and significant distortion and as long as they operate well within their design parameters, meaning a few watts at most for budget products.

Still, it would be very difficult to set this up as a controlled test as the above mentioned design parameters can be inherently different thus engineered into to core design of varying amplifiers.

Take a 'typical' Naim for example; High frequency bandwidth limited and with a low(ish) damping factor of around 15, both deliberate. They are partly responsible for the Naim 'house sound' ... subjectively dark, relatively full and propulsive with limited sound stage width compared to some others.

How could you make the Naim sound like say, the Pioneer next to it? Impossible unless you start alternating circuits of the Naim. You couldn't easily restore 'missing' high frequency that are not there anymore or increase damping without it. However, if that Pioneer has tone or even a loudness control, you are probably able to almost replicate the Naim sound signature to a 'T'.

I hear you say ... ' eek, loudness controlls, never on my nelly' ... . Whatever you call it, loudness or bass, treble even mid controls ... it is essentially what amplifier designers engineer into their products anyhow. They do this by careful part selection, circuit layouts resulting in a 'fixed' tone control. Think of it as a 'pre-set' for another term ... without the ability to change it.

Where big, powerful (or just very well designed) amplifiers differ is in maintaining these sound signatures at higher volume. Transient response as well as maintaining supply over longer than milisecond windows to difficult loads and lower frequencies are the perogative of good power supplies. That costs money.

At lower levels, one, two or perhaps ten watts, enough to play fairly loud in domestic circumstances, most decently engineered amplifiers can probably be made to sound very similar, especially if you have tone controls.

regards

Never is Ben. Its just my take on it ... sorry for some reason I can't post a new thread in one go!

Very nice systems you have by the way. I had a look through some of the reader photos recently.

Hoopsontoast, I am not sure if you are the same guy as over at DIY Audio? If you are then you know a lot about amplifier design and perhaps agree with me. I would be interested to hear your take on the thesis but in essence, I agree with you that not all amps sound the same, if perhaps not for the same reasons other people assume.

regards

I'd have thought if the specs are the same, the sound is pretty much going to be the same too.

Probably a slightly simplistic view, no offense intended, but I understand. Unfortunately, specs are rarely the same even if they look superficially (on paper) similar. It would be difficult to find two different brand amplifiers, even at the same power rating, which use identical components and layout, starting from transformer and ending at the output stage, much of which can be responsible for sound signature.

But, as afromentioned, I think it is possible to almost make them sound the same so I agree with you to an extend.

regards

Does the Harbeth challenge need to be posted again?

There are some sure fire winners of some very expensive speakers on this forum.

IMHO the answer is no. I recently went from a Naim SuperNait to a Sugden Masterclass IA4 and the difference (at least to my ears) was as obvious as night and day - greater detail, definition and (surprisingly) more PRaT and power.

Then again, I recall that Harbeth's chief designer Alan Shaw says that his speakers will sound the same when paired with any properly designed amp and has a standing challenge to anyone who can correctly identify different amps in a controlled, scientific test.

 I believe the incentive  is a pair of Harbeth's top-of-the-line Monitor 40.1s but no one has managed to win them yet.

Yes.  Except for when they don't.

Hi am on diyaudio but not as hoopsontoast. I dont know much about technical amplifier design.

Two similar design amplifiers 'should' sound the same, but they dont. A 1.5w SET WILL sound different to a 200w SS amp given its output characteristics. Two 1.5w SET amps based on the same tube (SV83/EL84 for example) might sound different with different tubes, which can be put down to manufacturing tolerances and differences in the tubes themselves.

You have to take into account the speaker its being used with. For example a monster 200w SS amp is not likely a good match for some 99dB full range horn speakers, where as the 1.5W SET amp is likely to be a better match, with its high output impedance rolling off the elevated treble in the full range driver.

This is obviously a wide mis-match example, very similar amps into normal speakers I would guess there would be less difference as long as the amplifier is not being driven into clipping or distortion.

But then I have heard (IMO) a difference going between very similar amplifiers (design and spec) into easy to drive speakers so really at the end of the day, its subjective.

If someone hears a difference (positive) in a change in amplifier, cable, cd transport or even cable lifters and other foo, and is happy to pay the price for an improvement to them, then fair play.

IME these sorts of 'tweaks' make little difference so I will leave it at amplifier make a big difference, but In My Experience, less so on other 'upgrades'.

Hoopsontoast, yes, certain tube amplifiers, expecially the very low powered ones, can respond differently and speaker loads/sensitivity will have to be taken into consideration. There are however plenty of valve powered amplifiers that have very low distortion (the main difference for perceived (and measured) differences other than frequency extreme variations due to power supply and output transformer limitiations (or induced frequency variations at different volume due to pot design/wiring, not unique to valve amplifiers by the way). My thesis is based on designs with similar engineering criteria. It doesn't include products with deliberately created (or, in some cases just badly designed) harmonic distortion as a means to change sound as mentioned in my OP (or no.4 I think due to my problems with this site)

regards 

Do all blonde ladies look the same? 

A quick listen to Arcam vs Cyrus will show a difference, or Luxman (AB) vs Bryston

Even Tube amps can sound different - Unison Research vs VTL, as an example.

Thanks dm 

Yup Gotta love the cosy listening room.

Yeah all exactly the same.. It's only because we expect them to sound different we hear the changes. Same with speakers, interconnects and source.. It's all a conspiracy