Hello koiman
Interesting question - which tube amp to drive a pair of M80s. This question calls for a slight digression - comparison between book shelf and tower speakers. The more I listen to towers, the more I realize I prefer book shelf speakers. I have auditioned M60s, had a pair of M50s, and use a pair of M60 like Michaura M665s in my HT system. I had a pair of M3Tis, have a pair of M2es, and use Michaura M55s and M66s (the former like the M22, the latter like the M22s but with a pair of Axiom 6.5" aluminun drivers instead of a pair of 5.25"s as used in the M22s and M55s. I prefer music from the smaller book shelf units because they sound more coherent to me, quicker and more musical. The towers all sound sort of like a collection of drivers in a box. I don't know whether this is a function of the cross-overs used or the nature of the beast.
My personal favorite set up is a pair of Michaura M66s driven by a 5 wpc SET Antique Sound Labs MG S1 15DT integrated amp. My second favorite set up is that amp driving a pair of Michaura M55s (x-overs modified with Caddock resistors and Jensen paper/oil caps), closely followed by that amp driving a pair of Axiom M3Tis. For some reason the M22Tis just didn't sound right in this set up. M50s sounded worse, even though the M50s, in their much larger cabinets, use the same 2x6.5" aluminum drivers as the M66s, though all the Axioms use a 1" tweeter instead of the 3/4" Merak style titanium tweeter used by the Michauras.
Anyway, I have a feeling that the M80s require more power to 'open them up.' The best bang for the buck in tube amps, and maybe any kind of amp, is the Antique Sound Labs Hurricane monoblocks. These list for about $5,000 a pair but can be had from Upscale Audio for about $3,200. Absolute Sound rate these amps as the best out there.
http://www.upscaleaudio.com/ check out used, demos and specials.
I think these 200 watt tube monoblocks should be able to get the most out of the M80s, but for me, I'd go with a pair of M3Tis, modify the cross-over, give up on the warranty, and get a nice $1000 or less SET tube amp.
Hope that helped.
