Electronics for Harbeth, Especially Monitor 40 series

I never thought about at atma-sphere but it makes sense now that Ralph brings it up. They are fast and clean. If the speakers are impedance friendly and that's the sound you want, they are fine amplifiers in my experience.

I have been using Spectral pre and amp with the M40.1 and have been very happy for the last 7 years. The M40.1 are somewhat amp friendly but have a lower sensitivity 84-86 db/1 watt/1 m. I do sit close to near field ~5-6 feet. I listen at about 75 db with peaks in the mid to high 80's max. 

I have 40.1's and I've tried many amps and integrateds.    Tube amps are superior in my experience.  Rankings as follows:

1. VAC PHI 200 (current amp)
2. VAC 70/70 Signature (130 pound beast, great on vocals and jazz)
3. McIntosh MC275 MKV (fun, gutsy classic amp)
4. VAC 30/30 (incredible amp with midrange to die for, but could use a tad more power)
5. Plinius SA-102 in class A (best solid state I've owned)
6. Bryston 4BST (decent value at used prices)
7. McIntosh MA2275 (too soft and mellow)
8. Musical Fidelity M3 Nu-Vista (awful gear... will never buy MF again)

Perfect time to chime in,
I do prefer solid state. Tubes a little to laid back for my ears.
I have 40.1 and by far my two favorites are
Plinius 103 and the new Bryston 4 cubed.
Imo they need a little muscle.

@dan31, Vinnie Rossi told me at Newport that he listens to all Harbeths in the same near field type set up. Six-foot equilateral triangle. I've never heard them set up that way, but anything that would keep the tonality and frequency distribution while increasing imaging and jump factor sounds like a step in the right direction to me