Best power amp for Quad 63

all the amps you mention should work well, if the amps themselves are working well

Thank you. 

I am using an Ayre VX-5 Twenty. Perhaps a used unit is available.

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.

@RalphKarsten from @ Atma sphere does post here.

Kent at Electrostatic Solutions did the restoration of my 57's. 

Futterman H3 OTL if you can find one in nice shape. I believe they were also sold under the Harvard Labs brand.  These were the original Futtermans built by Julius Futterman. Wonderful synergy with older Quad Electrostatics. The H3 was also available as mono block amplifiers.

Happy 4TH of July to everyone! 😀

You want more HIGHS with Quad's???

Well, my advice is a Phase Linear 700 from the old days.  It is as shrill as they get, and with the shrillness of the Quad's, you should be happy.

If you are my age, over 70, your high frequency hearing may be slightly less than it used to be...maybe get it checked?

Cheers!

For what it’s worth, I had the treble panels replaced on my ESL 57’s at a high end shop in the late 80’s. On a Saturday, they demoed them for me using a Spectral amp. It was a show stopper in a crowded store, mouths wide open. At home using the original quad mono blocks, I never achieved the realism I had heard with the Spectral. Good luck

i owned quads for years

i was also a cj dealer the pv11 is your problem the latej cj gear was way more transparent

you should just get a new preamp.

please give our store a call we have a great warm sondind but more transparent solid state preamp which we can send you

which should perk up that system

and still be sffordable for you

Dave and troy

Audio intellect nj

@fortepiano50 When I owned Quad63USAs I also found the best matches were tube amps in my case Berning ZH270 and Dehavilland 845 monos. I'd suspect that the Atma-Sphere M60s suggested would have also been a great match. 

OTOH, I understand SS adding punch. My Soundlabs are run w/Krell FBP-300 which trounced hybrid Lamm monos that I originally paired with them. 

IMHO, the Krell, Plinius, Accuphase & Spectral would all work fine, but I'd seriously consider tubes if you are open to that. One caution w/Spectral, when I bought DMA amp and preamp many years ago, I recall some atypical impedance specs that made use of both their pieces a best practice; some of their gear isn't suited to mate with other brands to quite the same extent as others. Do your research to be sure it's a good fit w/your pre. Cheers,

Spencer  

no doubt well made otl’s are especially well suited to drive esl’s be they quads, sanders, soundlabs, m-l's and so on

such amps do require quite a commitment from the owner, and some may shy away from these amps running with many many power tubes to maintain

i have had very good luck (and wonderful sound) with my trusty arc 100.2 on my esl63’s

furthermore one can also use a nice tube pre in front of a zero maintenance ss power amp...

Big thanks to everyone!  

• Atma Sphere M-60: I wanted this amp so bad but I didn't have enough for those and the Quad 63. Someday.
• I really like the Spectral and your advice on doing my diligence.
• I also like the idea of another preamp.  
• But, this is my favorite:
  

  richopp

  "You want more HIGHS with Quad's???"

  "Well, my advice is a Phase Linear 700 from the old days.  It is as shrill as they get, and with the shrillness of the Quad's, you should be happy.

  If you are my age, over 70, your high frequency hearing may be slightly less than it used to be...maybe get it checked?

  Cheers!"

Yes Rich, I had three years of six nights a week experience with two Phase Linear 700s, a Crown amp and a tri-amp sound system. They worked great for that application but were never allowed in my house. We ran two ESS AMT super tweeters and was recently excommunicated for mentioning using a dipole ribbon with the Quads.

I earned a living as a professional musician for over 20 years and played many genres but mostly classical. Now play in a British style Brass Band near Washington,DC. Shrill, you say. That is definitely the sound for a classical instrumentalist. Right?

I will agree that I am 70 and could have some upper frequency loss but my recent hearing test proved otherwise. 

In closing I would like to use a phase commonly used in the southern USA.

"Bless your heart!'

+1 fortepiano50

Re:Shrill... Yes.. what you said...

Keep loving your Quads and I would echo the recommendation for Quad amps.

@fortepiano50

I’ve been meaning to add my .02 here for a few days, but have been busy.

I’m sure that many of the recommendations above will sound good. The OTL amps, in particular, will have a certain magic. I auditioned a pair of well-regarded Futtermans and thought they were great. But I was put off by the potential hassle of re-tubing those amps.

I also owned, and really loved, a Sanders Innersound Electrostatic amp. This was a circa ~2000 version of his current Magtech amp. It sounded awesome.

However, I caution folks about using a Sanders amp with any Quad ESL which has the "crowbar" protection circuit. The protection circuit is basically a dead short. It results in the amplifier dumping its prodigious power into the dead short in an instant, which basically can destroy the amp. Ask me how I know. This requires sending the amp to Coda for repair and service.

My very strong recommendation is to use one of the Quad amps - I’m now using a 909 and am very satisfied. It’s the only amp in the world designed to work with the protection circuit. It isn’t flashy. Not expensive. But an extremely fine all-rounder. Won’t have the transparency of the OTL amps, but substitutes rock solid reliability for that last little tiny bit of detail. That tradeoff is worth it, in my book.

The advantage of an OTL on this speaker is due to the very high impedance the speaker has in the bass. This peak is not due to resonance. Solid state amps will throttle back their power into this impedance and so getting the speaker to play bass with solid state is problematic.

OTLs OTOH can make power easily into this higher impedance, which works well with the electrostatic characteristic. A lot of our customers have commented that with our amps they don't need subs to make convincing bass.

ESLs in general do not obey the same design rules that box speakers do. Most box speakers are designed around the idea of being 'voltage driven' which is to say that the amp driving them can act as a 'voltage source'; being able to make the same voltage regardless of the load impedance. ESLs work better with an amp that makes constant power with respect to load impedance. For that you need a tube amp with no feedback so its output impedance is high enough for this to occur (you can also do this if voltage and current feedback in the amplifier are done in equal amounts, but this is very rare in amplifiers!).

For more on this topic see:

http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html