Anybody else waiting for GaN and Purify to have a baby?

The "distortion signature" is just one of an infinite amount of things that effect the sound.

It is true that phase shift can cause colorations. But beyond that almost anything else that results in an audible difference is likely due to how it affects the distortion.

"Designed properly".......now that is funny. There is no consensus in high end audio as to what that means. 

This is true. For me, 'designed properly' (which I hope was easily inferred from my prior post) simply means that the amp will have a distortion signature that allows it to be neutral (while otherwise allowing the amp to be usable and reliable....). I don't regard most solid state amps as neutral because their distortion signature includes unmasked higher ordered harmonic distortion which is audible as brightness and harshness; literally the reason that vacuum tubes are still around. They aren't 'designed properly' IMO.

If all you need is a certain "distortion signature"......then why make a new amp? There are already amps with that signature.....nothing new there.

This is true as well. However the reason to make a new amp is simple: the amps that have had the right distortion signature in the past are all tube amplifiers. None are solid state. Class D offers the ability to have a similar distortion signature, but at a much lower level, easily over a magnitude lower. This allows the amp to also be more neutral. A class D amplifier also does not need regular service, makes a lot less heat and is more compact. If you can offer all those advantages over tubes with the same smoothness and detail thru the mids and highs why on earth would you **not** do that?


The trick here is understanding how the measurements correlate with what we hear. This is rarely done in the spec sheets which give you very little information about how the circuit actually measures. This is why I'm talking about the distortion signature since it is something that can be easily measured with today's equipment and its predictable that if you get it right the amp will sound like music to the human ear.


Here are some aspects of a proper distortion signature:1) the THD measures the same at 100Hz, 1KHz and 10KHz (usually only the 100Hz distortion is shown in reviews and on spec sheets)2) the primary distortion components should be the 2nd and 3rd harmonics (which are nearly inaudible to the ear) in sufficient amount such that they mask the higher orders. A tube amp makes more higher ordered harmonics than almost any solid state amp, yet sounds smooth because the lower harmonics are masking the presence of the higher harmonics.


If you don't get these two things right the amp will not sound musical and organic.


The chief engineer at Scott once said "If it measures good and sounds bad, -- it is bad. If it sounds good and measures bad, -- you've measured the wrong thing."
It was true when he said it and its still true today.

Class D offers the ability to have a similar distortion signature, but at a much lower level, easily over a magnitude lower. This allows the amp to also be more neutral. A class D amplifier also does not need regular service, makes a lot less heat and is more compact. If you can offer all those advantages over tubes with the same smoothness and detail thru the mids and highs why on earth would you **not** do that? 

Does this notion give anyone else a slight bulge in their pants?

@soix 

in the front or the back? 😆😆😆😆😆😆😆

I had been on the class D roller coaster for over a decade and was about to throw in the towel. Then someone here on this forum mentioned the AGD Audion, i thought ok i will give these a try. Needless to say i was taken back everything my WAVAC 300b could do the AGD's could do better. And i have the entry level amps.

So yes you can have the SQ of a tube amp and take the best of a SS amp within a class D amp IF designed properly from the start. Having to do mods tells me design is in question.

in the front or the back?

Yeah I was definitely referring to the front and not the back — not that there’s anything wrong with that.

Having to do mods tells me design is in question.

Not sure about that — coulda just been cost constraints in designing to a price point.  Always trade offs.  That’s where modders and model upgrades (looking at you ARC) come in.