Oh, I also have a pair of VAC Phi 200 amplifiers, currently used as monoblocks, but could each be used in stereo mode, one channel supplying each quad in the stack. They are 200 watt KT88 amps, and I believe that the speakers are protected by clamp boards.
Stacked Quad Questions
I am soon taking delivery of a pair of stacked quads, recently rebuilt by Electrostatic Solutions and with custom Sound Anchor stands (steel stands, with speakers set between aluminum side panels). The aluminum side panels place the two speakers on a vertical plane with the transformers back-to-back in the middle, and no middle surface to which a tweeter could be mounted. I can also get custom side panels made that would accommodate other configurations (convex or concave speaker positioning, a middle panel in which tweeters can be inserted, etc.). I have had single quads before (Wayne Piquet rebuilds), and I have the following ancillary equipment that worked well with the single quad 57's: a Bedini 25/25 solid state amp, a pair of VTL Tiny Triode TT25 EL84 monoblocks (most recent build), a pair of Cary SLM70 EL34 monoblocks, a pair of Townshend super tweeters, and a pair of Magnan signature speaker cables.
My questions, in order of priority, include:
My questions, in order of priority, include:
- There are 3 ways to wire these speakers: a single amp driving a stacked quad wired in parallel, or in series, or two amps (or two channels) each driving a single quad in the stacked pair. What are the advantages and disadvantages of these three options? Does choosing one of these options disqualify any of my current amplifiers? Note that I don't have four channels of the same amplification for the third option, and would prefer to use my current amplifier arsenal, so I would have to mix and match amps for each stacked pair, which might require a means to balance output.
- Electrostatic Solutions (Kent) prefers the geometry of this mounting (2 speakers on a flat plane) to convex or concave configuration. He places the speakers kind of high in order to deal with the limited vertical dispersion of the tweeter (beaming), so that the midpoint of the bottom quad is at seated ear level. The stand is fully height adjustable, so there is plenty of flexibility there. Any other thoughts about the mounting geometries?
- I know that the Mark Levinson HQD stacked quad systems used supplemental tweeters. I have the Townshend super tweeters, which claim to " accurately reveal high frequency detail above 6kHz" but seem to emphasize frequencies above 20kHz. I also have nowhere to mount the supertweeters - I would have to strap them to one leg of the stand. I know that Kent doesn't believe that stacked quads need additional tweeters. What is your experience? I could change the panel configuration so there is a middle surface for tweeter mounting. Is it necessary to use expensive types of ribbon tweeters (e.g. the Deccas used by Mark Levinson), or are there more affordable and excellent ribbon tweeters now available? How does one wire the tweeters - in parallel with the stacked quads with a simple capacitor/resistor as a passive Xover?
18 responses Add your response
Good for you; I have never run them stacked, but will keep an eye on this thread. Kent recently restored my old pair and even as single panels, they sound the best ever. I did use Decca and Sequerra ribbons back in the day, and mounted them on DIY stands separate from the speaker so they were positioned above the (lower) ESL. No woofs? |
I have a couple packets of literature from back in the day on setting up Stacked Quads, I haven't been able to lay my hands on them since I moved. I think it was more about building the frames and positioning than wiring, but there are some people running stacked systems who could tell you what they've done. Yeah, the bass on a single pair is taut, full of tone, beautiful really, just doesn't go down deep. And when you get them up on off the floor (which I i did years ago with the Arcici stand) you lose some of that floor reinforcement. Perhaps the double pair makes up for it, I never had success with subs but that was back in the '70s and early-mid 80's. Right now, running my single pair without any supplementary speakers. They are still the best mid range speaker I've ever heard. Did you know Faye Dunaway apparently had stacked Quads- crazy, right? |
Peter---I had stands made for stacking Quads back in the early 90's (three sheets of 3/4" MDF glued together---2-1/4" thick!), and designed them the same as yours: The bottom panel at ear level (36" above the floor), that panel upside down and butted right up against the top panel. Both panels were perfectly vertical to the floor, no angling. By the way, I have a Bedini 25/25 that I no longer use or have a need for. If you would like it (so you can have a 25/25 for each pair of Quads), I can list it for sale here on Audiogon, and let you know so you can watch for it. |
I have had Quads since 1982! Presently have two pairs - only one pair in use right now. My amplifiers of choice are: Bedini 25/25, Futterman H3AA's and Futterman Harvard Music. I recommend selling the VTL pair and buying bdp24's Bedini so you can have one amp drive a stack with one channel per speaker. And I think the 25/25 sounds the best of all your amps! The VAC amps are just too powerful for Quads (20 volts max input)! As regards configuration of a stack, my preference would be convex (bottom Quad inverted 3 to 6 inches off the floor and top Quad tilted a bit forward). No need for add-on tweeters - will just mess up the sound (the Quad's treble is just fine and matches well with the bass/mid panels). Someday I will set my two pairs up as a stacked system! Good luck! |
We've had a number of customers over the years that have run stacked ESL57s. Dave Magnan of Magnan cables did that right up to when he retired. With our amps, its best to simply wire the speakers in series. With most tube amps employing an output transformer and with solid state, parallel seems to work best. Everyone I know with that speaker is pretty loyal to it- some have owned them literally for decades. |
peter_s We did a lot of experimenting (paralleled and in series) driving stacked 57's with a Decca Kelly ribbons on top from 10khz up. The best sound we got by far was paralleled wired, driven by a good solid state high biased into class-A amp amp, similar to something like the John Curl designed Parasound Halo JC1's in high bias mode. The sound was stunning that was well extended at both ends, with a midrange that was rich and full bodied without sounding fat/bloated, tight rhythmic bass and sweet extended detailed highs that floated in space front of you. Cheers George |
@roberjerman. The Electrostatic Solutions rebuilds have protection circuits and I believe are safe for all input levels. From their website: Both the ESL63 and the ESL57 require an amplifier that is highly stable into reactive loads and has a large, stable power supply. We have found that amplifiers in the 50-100 watt range are ideal for either speaker. Protection circuitry in the speaker will allow the user to choose amplifiers of any output without fear of damage. Dual mono designs will perform the best with both speakers. |
@peter_s - re amp power, when I got this pair of Quads in 1973 I eventually ran them with an ARC Dual 75a (which was brand spanking new though very old school by today’s standards- still have the amp). But now, I’m running mine, restored, with a pair of Quad IIs, which have very little power and usually sound too romantic- they just gel with the speaker, at least using GEC KT 66s. So, bigger isn’t necessarily better here. Not suggesting you buy all different amps, but the synergy with the little old Quad amp is pretty amazing. BTW, i'm very excited for you, i have long wanted to run a stacked pair. |
Most of our Quad customers run the M-60. If its the ESL63, the MA-1 can drive the speaker louder than any other amp before the stock limiters kick in. If you've upgraded the protection that's a different story. If stacked ESL57s the M-60 is the only amp I've heard of being used. We've had a lot of Quad customers over the last 40 years- OTLs and Quads have a long history together, going back to the 50s. |
I have no experience specifically with Quad stats, but do have many years with Soundlab's (and before that, Martin Logan's). Thus, with Ralph citing the positive history with his amps and Quads, I would at least give Atma-Sphere's OTL's an audition. Soundlab's and my recently purchased Atma-sphere MA-1's create as good a match as I've ever heard! Some of my comments about my experience with various amplifiers and Soundlab's can be found here: http://www.soundlabowners.com/cgi-bin/yabb2/YaBB.pl?num=1393874625/30#30. -Mike |