Best amp for Avalon Eidolon speakers?

Try Atma-Sphere MA-2 or large CAT amps. I personally prefer the Avalons with tubes. As always, system dependent.

I heard them driven by a pair of Spectral monos (don't know the model but I am told it is about 300 w into 8 ohms). The sound was out of this world.

I think that large tube amplifiers will produce the best result with the Avalons. Try CAT JL-2 or JL3, BAT 150SE, ARC REF. 300, Jadis, maybe AtmaSphere MA-2.III.
If you don't want to go tubes, I think that Accuphase A-50V as monoblocks, Halco DM-58 or DM-68, Goldmund 29M.
If you want something that sounds good and carries a more human pricetag I think the Bel Canto EVO2 as monoblocks could work really well with your speakers. If you choose the last resort be careful not to match the system with bright or hard sounding source. Perhaps try the Audio Aero Capitol Mk. II with the Bal Cantos and the Eidolons. Match made in heaven if you ask me. For wire try the Argento VDM reference.

By the way the Eidolons are glorious to say the least.....

Best regards,

AudioMGU

The Avalon Diamonds were driven at CES by Tenor or Lamm. Sound there and with Kharma Midi and Rockport were the rooms that stood out. All three were using Tenor or Lamm and all with Audio Aero CD players driving the amps direct, if I remember correctly.

Try to demo the Tenors and Lamm's, along with the Atmasphere's already suggested here. I think it worth a shot to listen to the Wolcotts ( properly tubed out ). These provide amazing results on my Soundlabs. The Wolcott would be a relief for your budget after having just purchased Avalon's. At least half retail the others, and a third the price of the big Atmasphere.

The Atma-Sphere MA-2's are a good match with the Eidolon's here. Excellent control, extremely quick, with beautifully natural timbre and harmonic overtones on acoustic music.