Best power amp for Quad 63

Quad 606

I used an ARC Classic 60 when I had Quad ’63s- they were Crosby modified. That amp was not as warm and "juicy" in the old tube sense as previous ARC amps I had owned and used- Dual 75a (still have it, sitting idle); Dual 70 mk ii (nice amp).

At the time Crosby was doing the mods, he was working with Spectral. Though the Spectral sound was, to my ears, very analytical and "accurate," it lacked what I believed were some of the ambient cues-- but if those are on the recording, a good solid state amp, like some of those you are considering, should convey that information. They were used as part of a system, the Crosby mod on the ’63, the Spectral amp and big Entec subs. I heard that system more recently- within the last 20 years and it held its own.

I’ve been doing horns for a while- easily as transparent as the Quads in the mids- (I still use Quads in another system, a pair of ’57s I have owned since the early ’70s, with Quad II amps/GEC KT 66s, etc.).

The 63 may be a more overall reliable speaker than some of the later ones, which I never owned. Good luck= there’s music in them hills. :)

Thank you so much. You have connected a lot of dots for me. ;>)

I use McIntosh MC-60’s with my ESL-57’s and really enjoy the sound the combo produces.  My 57’s have been updated by Electrostatic Soluitions and the Amps have been updated by Yves Beauvais.

I have used many amplifiers with my Quad speakers, and owned all Quad ESL models : 57, 63, 988, 989, 2905, 2912 (as well as many other electrostatics). For 63 I would recommend Atma Sphere M-60. This is, by far, the best match for 63 model and it will outperform all amplifiers which you have listed. Stay away from Accuphase and Esoteric, as these are not realy the best choices you can do for ESL speakers. Spectral will do the job as well as ML, Krell, Plinius but you will not have with any of listed amplifiers all the beauty of sound you can have with a well made tube amplifier. Electrostatic speakers are know to work very well with tube amplifiers, and with OTL technology in particular. Some other tube amplifiers will work particularly well (for exemple EAR Yoshino V12, Air Tight models but their price is not cheaper than M-60 and OTL gear will outperform those "classic" tube amplifiers in every single aspect : transparency, bottom range, texture, natural rendition etc. If M-60 is not in your budget, try to find some other OTL amplifier, or save money and get back to M-60 later. You like Quad speakers in the first place for their utmost beauty of the middle range and transparency. In this regard matching your stats with OTL technology is the right path.