Solid state amp vs tube amps

... And yet I went out and bought a Melton, P/P, KT-88 tube amp and much prefer my 20+ year old Yamaha RX-Z9 in "Pure Direct" mode. The Yamaha is a very high current amp and really bring out the high end of the Heils with so much more detail and the bass is fuller and more distinct. And I am a stickler for detail.

Use a good set of phones or monitors and the differences are obvious. Volume levels were matched to within a couple tenths of a dB. The Yamaha has >30,000 hours and the Melton has about 60 hours on it. The speakers have undergone modification since the videos, but the differences are still very audible.

Anyway a big difference in sound...hard to use "quality" as a measurement of a subjective essence such as sound. 

+1.  They do sound different.  "Quality" may be a subjective term.

@marquis4099 The differences you usually hear have to do with how tubes and traditional class A or AB solid state amps make distortion.

Quite literally the 'sonic signature' of any amp is its 'distortion signature'.

I used the word 'traditional' as there are class D amps now that have a distortion signature much like tube amps do, and unsurprisingly, sound very similar as well- but with greater transparency owing to lower distortion overall.

I use a tube preamplification to help my active speakers...

It work...

But if you think tube/s.s. make a difference and it does, acoustics control of the room had more impact than almost any upgrade improvement... Acoustics does not replace gear design improvement for sure, nothing does; but acoustics control overpower anything else.

I just put a resonator in my room today...

Huge difference when well tuned...The difference in effect of the S.Q. aspects of sound when only one resonator is added at the right place and tuned as it must be , exceed all my other gear change since the begininng of this acoustic corner for near listening...

Here is an interesting article on this subject!