Amplifier brand/designer with the most unique and consistent “house sound?”

Here we go with semantics again.. 
Pass tunes their amp to sound its best based on a group of people listening and adjusting the final sound to their liking. They always seem to measure well and with low distortion according to the reviews. dartzeels lastest amps don’t really measure well either but that doesn’t stop them from being considered amongst if not the best out there.
First watt is a different animal.. minimalistic amps , low power with no feedback, little feedback, added distortions, etc  They aren’t mainstream and need to be properly matched. Sometimes they feel the need to add feedback to get a better sound, Sometimes they don’t use feedback at all. Whichever FW amp you choose, it’s clearly described on how it’s designed and what to expect.. I didn’t choose my amp based on specs or types of supposed distortions.. but what it sounds like in my system..  

I didn’t choose my amp based on specs or types of supposed distortions.. but what it sounds like in my system..  

And there is someone like me that choose the worst measuring amplifier that i could find!

If we say like this: that amplifier in my dedicated 2ch symmetrical and treated room sounds actually great.

But if we for one second imagine that the worst measuring amplifier sounds actually "good".

Then maybe we can start to reflect over how much or little measurements actually says about sound quality?!

OK I will go out on a limb here and post a YouTube video of my system playing a track captured by my crappy phone (maybe some sound quality is preserved somewhere to indicate that a clone of pass ACA with <5w/ch that measure terrible)

"Enjoy":
https://youtu.be/_zHy37X192g

I think this is a very educational discussion.  Well done peoplem

@atmasphere writes 

You also **at the same time** must have the same distortion percentage at 100Hz, 1000Hz and 10,000Hz. Many solid state amps have excellent distortion figures at 100Hz, which is why they are usually measured at that frequency. But if you measure at higher frequencies, like 10KHz, you find that the distortion is higher.

If you get rid of distortion and phase shift across all frequencies, will all amps sound the same?  Should they?  Even with different topologies, parts?  No more house sounds?

What amps have taken this to the mathematical extreme?

If you get rid of distortion and phase shift across all frequencies, will all amps sound the same?  Should they?  Even with different topologies, parts?  No more house sounds?

If their output impedance is also the same then at that point, yes, they will all sound the same assuming their power supplies are up to the task.

I would not characterize doing this as a mathematical extreme. Its simply what you do if you want to get it right.


The key is getting enough feedback and at that point it won't matter if its tube, solid state or class D. This is almost impossible with tubes as there are usually too many frequency poles resulting in a low 'Phase Margin'. If the phase margin of any amp is exceeded when feedback is applied, the amp will go into oscillation. This is one reason why tube amps tend to have less feedback than solid state, the other being that they are also inherently more linear and don't need that much feedback to have acceptable distortion figures.


Designers who have been up to the task of installing enough feedback in traditional solid state designs are rare. But it appears that the Benchmark and the Soulution are two amps where this is exactly what has been done.


In class D this is possible though a different means which is to add so much feedback that the phase margin of the amp is exceeded, causing it to oscillate. The oscillation is then used as the switching frequency. Such amps can employ quite a bit of feedback and the sound of them is really all about how well the power supply is built.