Quads are a pain the ***, but worth it?
I've used Quad ESL-63s for many years as my main speakers. I haven't heard another speaker that I like better overall yet, and I’ve heard most of the ones that cost as much as a luxury car.
But I have had a lot reliability issues with mine. It’s really a shame that these speakers are not more reliable. Despite using subwoofers to lessen the burden on the ESL panels, and using moderate tube power (both transformer coupled and direct-drive) with some discretion in volume levels, I have had to replace every single panel (8 in the pair) through the years. I have enough panels saved in a stack to build a new pair if I ever set up to make my own Quad panel repairs, with a few to spare. I do live on the ocean in Florida, so humidity and salt are concerns, but my speakers have always been in air-conditioned spaces with windows shut. I run mine “naked”, without the socks and metal grills (I do keep the film dust covers intact). While this greatly improves the sound, and shouldn’t impact reliability, I’ve found a particular problem that I should mention. In a prior room setting, the back side of one of my naked speakers would catch direct sunlight streaming in from a window at certain hours of the day. I had several failures on the stator sides facing the sunlight. It seems that the UV was sufficient to accelerate the aging of the adhesives holding the stator boards to the plastic louvers, or it could have been thermal expansion stresses too. The stator boards would come loose, especially at the corners, causing arcing onto the diaphragm, which if not caught in time would result in perforations and then tearing. This failure mode is not unusual even in panels not exposed to the sun, but clearly it was worsened by my situation. Needless to say, I draw the drapes now.
I removed the rubber plug covering the hole over the neon charging bulb. I am obsessive about watching the pulse rate of these bulbs. They are often the first indicator or arcing, before snapping sounds are heard. I am weary off fixing these speakers, but they sound so neutral that I haven’t switched yet, although I am working on my own DIY ESLs with the hope of one day making a design I like better than the Quads (a lofty goal, I know). So I cannot unconditionally recommend the Quads to my friends without making caveats about the virtual certainty of needing future repairs.
