Do those versions have the same volume constraints as the early models? Once listened for a few hours near field...sounded amazing but I like to listen at moderate volumes. I don't know much about the evolution of the product, they they improve upon the power handling/efficiency?
Hi! I saw the reference to the Qual ESL 988 that we have in the showroom, and thought it might be OK to address this question. The 988/989 are much easier to live with, and power, than the earlier ESL-57 and ESL-63 variants. Each speaker uses 4 panels, a revised power supply network, and a stronger armature. All of these things reduce or eliminate the arcing and vibration that occurred on earlier models when connected to higher power amplifiers. The ESL-57s for example would top out at 12-20 watts per side before the arcing risk became apparent. Given their relatively low efficiency, that meant a listening position that was relatively near field was necessary. This is not the case with the 988s. I have had them connected to a Plinuis 9100 integrated (90 wpc, Solid state, Class AB) and an Audiomat Arpége tube integrated (30 wpc push-pull tube integrated which "switches" from Class A to Class AB operation at 15 watt output). Either amplifier provides plenty of power for the 988s, and although the presentations are vastly different between the two amps, the enjoyment and clarity of the music, especially vocals, is astonishingly good. And since the 988s are low on efficiency (86 db), even when you turn the volume up, you still get an amazing wrap-around presentation.
The things that make 988s different: They are a true dipole and therefore need a lot of room from the back and side walls to really create that sense of depth and height that Quads have been known for, for almost 70 years. In my room, I had to move them out from the rear wall about 8 feet, position them relatively close to one another (about 8 feet apart), with a slight toe-in, and raise the front legs by about 3/4" to tile them back slightly. I have 13' ceilings in my showroom, so your situation will likely differ, but the point is, placement is key.
Hope this helps. If you are indeed interested, feel free to DM me and we can discuss further and work out the details. I can also put you in touch with Sheldon if you have technical questions about his process, but his web site outlines all of the steps be takes in a restoration.
Finally, if you are still looking for a more traditional stand-mount dynamic speaker, I would be remiss if I didn't mention that I have very limited quantities of the HHA Cionnsaile Monitor available. They play nicely with PS Audio equipment, as well as the aforementioned Plinius and Audiomat, the Plinius Inspire 880, Musical Fidelity M6si, Heaven11 Billie, and the Sudden Bijou system which is only a 15 watt Class A setup, but plays remarkably well. More info on the web site:
www.holthill.com