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Quad ESL-63 and low-powered amps; Sun Audio, Atma

Looking for opinions about suitability of low-powered amps with my 63's. I currently have an Audio Note M3 pre, CJ MV-60 amp. Importantly, I cross the Quads at line level at 100 hz, first order with nice Vandersteen MH-5 crossovers to Vandy 2wq subs. So the main amp is relieved of much work below 50 hz or so.

Specifically, I am looking at Atma-sphere s-30 MkII OTL 30 watt amp, and possibly even a Sun Audio 2a3 SET 3 watt amp.

Given my crossover, does this lighten the load (power or impedance) in such a way that these amps would work fine? I imagine the Atma will have no issues, but what about the Sun?

Finally, I would love to hear any opinions about the relative sonic characteristics I might hear between the CJ, Atma and Sun. I listen to 50% acoustic jazz, 25% classical, 25% rock. 60% on vinyl... SOTA w/Grace 714 and Grado Ref Sonata1. CD is CEC transport to Audio Note 3.1 Signature. I value musicality and rich midrange over endless detail and "neutrality".

Thanks all.
montaldo
montaldo OP
213 posts
 
Also, I didn't want to lead with this, but my sonic priorities lean more toward midrange magic and musicality. I am not one who seeks ultimate detail, "neutrality" in the audiophile sense, etc. I play at pretty moderate volumes, and never turn it up to extreme volume. So I am very curious about 300b and/or SET sound. But I am keeping my quads, so does this leave out SET entirely?
Another possible amp is an assemblage 300b push pull that might be fun to try. At 18 watts (I think) it should have enough oomph since it doesn't need to do much below 50hz?
atmasphere's avatar
atmasphere
12,176 posts
 
Montaldo, you might want to look at this post:

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1420484322&openflup&51&4#51

and this link:

http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

Unless you have a very small room, you will not have enough power with a 300b-based SET. They only have 7 watts. You need more like 50-60 as a minimum to really make the speakers sing in the average sized American room (17' by 20' or so).

Quads go lower than 50Hz, unless you are cutting them off with an electronic crossover. Actually they can make quite convincing bass!
montaldo OP
213 posts
 
Correction the assemblage is single ended and 8 watts. Looking at so many amps I got them confused.
marco1's avatar
marco1
617 posts
 
I don't think you can go wrong with CJ and Quads. It's more a question of whether you like the older CJ sound that you're getting with the MV-60 or the newer, more neutral and detailed CJ sound. I ran my 63's with several different amps including Music Reference RM-10's both in stereo and then mono blocks, and CJ Premier 12's. CJ combined with the Quads was always a step above everything else. Also, don't necessarily agree that you need at least 50-60 watts with the 63's. My Rm-10's in stereo at about 25 watts did just fine in a 16'x 24' room at all but very loud volumes with all types of music but some Classical.
roberjerman
4,319 posts
 
No single-end tube amp will work well with the 63's because: sensitivity is low and the impedance curve varies from high to low (30 ohms to 2 ohms). All single-end amps have rather high output impedances (2 to 8 ohms). They will NOT have a flat frequency response into a speaker without a flat impedance (Ohm's Law!).
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