Which amp matches best my JM Lab Mezzo Utopia ?

As a current SET owner my Audio Valve Challenger Class A tube mono amps sound much better than any SET I have owned and I have owned over 30 SET amplifiers. SET are just a wee bit better in the midrange and its slight but everywhere else the AV stomp on my SETs.

Johnk,
What amplifier have you compared to AV Challenger?
Do you use also Jm Lab speakers?

All,
I would like to ask you this :
Which amplifier would you prefer
- Air Tight ATM 211 or
- Wyetech Topaz A Mono

for use with the Mezzo and why ?

The Topaz M has great reviews , AT also.
I have auditioned the Air Tight 211.
It is awesome.
It has Tamura transformers .
These simply sing.
One thing only is that it has noise (audiable).
I have not auditioned the Wyetech Topaz.
The Topaz M is obviously more powerful and seems to have
more robust power supply.
Because of this my preference has gone to the Topaz so far.
One thing which makes me feel uncertain still is that the Air Tight is transformer coupled while the Topaz is capacitor coupled .
The capacitor introduces phase shift as fas as I am aware.
Will I get the direct immediate sound with the Topaz the same as or better than the AT 211 ?
Any suggestion is welcome.

I would suggest that you need at least 100W with a transformer that can drive the bass woofer. I have a pair of JM Lab Alto Utopia and tried a few tube amps. Then I found that a hybrid amp is the best for these speakers.

I am happy with my Counterpoint NP100 platinum: 100W at 8ohm and 200W at 4ohm.

Aleko, I would like to respectfully suggest that you're definately over-thinking this whole thing about selecting an amplifier . . . and this is coming from somebody that very much likes to understand and think about the technical aspects of audio.

But the pile of opinions and discussions above, spanning almost three years . . . this is WAY more information than you'll ever need. Probably time to simply listen, think less, and don't second-guess your ears.