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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

Showing 1 response by georgehifi

georgehifi's avatar
georgehifi
10,312 posts
 

The 63’s have 4ohm load from 6khz-12khz and then an even lower (epdr) of 5ohms combind with -40 degree phase at 14khz.

This indicates an amp that needs to be able to drive 4ohms as it’s best feature, not as a secondary feature. Which means (for tube if you can get it) an output transformer that’s specifically wound for 4ohms use, not 8ohms with a 4 ohm tap.

https://www.stereophile.com/images/66Quadfig01.jpg
" Dropping below 6 ohms below 50Hz and between 5kHz and 18kHz, with minima of 3.5 ohms at 10Hz and 13.85kHz, this represents a reasonably demanding load for an amplifier to handle. Tube amplifiers would be best used from their 4-ohm tap (if they have one), though any solid-state amplifier that more or less doubles its power output into 4 ohms compared with 8 ohms would have no problems driving the Quad."

Cheers George
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