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how close in sound can a tube and ss amp sound ?

i have observed threads requesting advice regarding tube sounding solid state amps, within a price point.

i wonder how to confirm such a request.

in addition to recommendations, what about comparing a particular ss amp to a particular tube amp using an experimental design where bias, or preconception has been eliminated ?

has anyone tested the hypothesis that he/she cannot detect the difference between a tube and a ss amp, within the same power range, price point and minimizing interaction problems, such as impedeance mismatches ?

on the other hand if someone is seeking a tube-like sound out of a solid state amp, i would assume that one would use a "classic" sounding tube amp, e.g., cj mv 45, cj 75, cj 100, or cj mv125 as the tube amp and try to find a ss amp that is indistinguishable from the sound of the classic tube amp.

i have found that many ss amps differ with respect to bass and treble response from many tube amps.

in my own case, i would love to find a 120 watt ss amp which sounds like my vtl tube amp. unfortunately, i am not optimistic.

in other threads, some people have stated that it is impossible to find a ss amp that is "tube-like", in the classic sense.
mrtennis
audiofeil
4,011 posts
 
>>12-29-10: Mrtennis
it would seem that one of the salient factors distinguishing the sound of some tube amps compared to some ss amps is their performance when operating in a clipping mode<<

Salient?

It's irrelevant.
atmasphere's avatar
atmasphere
11,913 posts
 
Audiofeil, in this case Mr. Tennis is right in some circumstances. If the amplifier is being clipped only on peaks, its behavior with that clipping will have a lot to do with its sound.

If you have a transistor amplifier and a tube amplifier of equal power and gain, such that either is clipped on peaks only, what you will find is that if the tube amplifier is built right, instead of outright distortion or excessive brightness, it will simply seem to compress right before audible distortion onset.

If for example the speaker is 90 db, and the amplifier 50 watts, this clipping behavior can be pretty important as there can be plenty of opportunity to clip the amp. It is situations like this that have led to the idea that tube amplifier power is often thought to be greater than that of transistors.
mrtennis OP
3,295 posts
 
why do some ss amps seem to perform poorly in the range 1000 hz to 5000 hz ?

they often sound like there exists a peak somewhere in the above mentioned region.

whereas, many tube amps, sound more pleasing in the aforementioned range.

could it be that some tube amps are subtractive ? , even though both ss and tube amps may measure well.
audiofeil
4,011 posts
 
Very few people compare amplifers based on clipping.

It's irrelevant.
atmasphere's avatar
atmasphere
11,913 posts
 
Audiofeil, my point is that many people indeed *do* compare clipping behaviors, only thing is, they don't know that that is what they are doing. Clipping can occur without the amplifier being outright distorted. Tubes have a much more graceful clipping behavior, which accounts for the idea that we have all seen before that 'tube watts' seem to be more powerful than 'transistor watts'.

Mr. Tennis, the range that you are talking about is the realm of the odd-ordered harmonics that I mentioned earlier. It is very challenging to build a transistor amplifier that does not produce a coloration at these frequencies, due to the way our hearing perception works. On paper you will find almost any transistor amp compared to almost any tube amplifier to be perfectly flat in this region.

IOW, we hear distortion as tonal coloration. That is why two amps can measure flat and sound so different. Now there is another reason, read this:

http://www.atma-sphere.com/papers/paradigm_paper2.html

Quads are a Power Paradigm technology, which means if you used a Voltage Paradigm technology (most transistors) on them, you will get a tonal anomaly, in this case brightness.
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