Amp-preamp, Integrated paring with Magico A3

You mentioned T+A and an affinity for tubes. I own a PA 3100 HV paired with Harbeth 40.3XDs which on paper are slightly less efficient the the A3s.

I was drawn to the amp after owning 3 different tube integrateds because of the high-voltage design that claimed to be more tube-like, and I love it. 
 

It fills a really large space with amazing sound effortlessly. It rarely comes out of class A as the meters rarely exceed 10 watts playing loud and crystal clear 40 feet from the speakers. In the sweet spot 10ft away the sound stage and imaging is great. 
 

it is warm but detailed and far from clinical. 
 

They are not cheap but will power almost anything you may own in the future.

They occasionally appear on the used market (unsure what your budget is).

I also owned a BAT hybrid integrated that was good but nowhere close to the T+A, but to be fair it was less than half the cost new.

I get my tube fix from a tube DAC and tube phono.

FWIW…

Good luck in your search.

@glennewdick 

I heard the A3 driven by an Aavik (Group Denmark) Class D integrated amplifier.  The sound was powerful but soul-less and the system did not sell me on the speakers.  Amp synergy is going to be extremely important with your speakers to make them as enjoyable as possible.  

Since they need a soul along with above average power hence the suggestion for a lush tube preamp with 6SN7 tubes (tube rectifier can also help) as well as a clean Class A or AB power amp.  

If you want to stay Class D the best most soulful sounding amps I have heard are from AGD , specifically the Audion.  Really nice sound that should complement the A3s.  Good Luck !  

I have A3's from the first run. Amazing speakers. I run them with Krell FPB 300cx power amp and VTL 7.5 iii preamp hybrid with two 12au7 tubes. Will not change a thing, probably ever! Give these speakers high quality juice! Neal

@glennewdick

I was privilege to hear a Majico S3 paired with Gryphon Diabolo 333 and all I can say is Wow. it's past my $$ budget so all I can say it is worth its price. 

the sound is spectacular, loud and instrumentally accurate. powerful and immediate. it touches the senses. I was about 15 feet away and I can feel the awe of the concert. Yup, the S3 can do its thing if it is powered correctly and beautifully. 

if cost is to be considered, Try this, a Pass Labs X350.8 Amp with a Linear Tube audio Microzotl Pre-amp. I am a Pass guy, but the gryphons are in a different league all together

Good luck

I would not pair Magico A3 with Pass amp as it would double down on the already not exciting delivery of the A3s.
They need a fast and lively amp. Simaudio Moon amps could be a good match. I would also try upper model Shunyata cables with them. They can benefit from transparency and speed upstream.