Question:
I have a used pair of ESL 63 USA Monitors. When I play them moderately
loud they cut out periodically. They come back on quickly. There is no
problem at all at low to moderate volumes. I have used different amps
and pre amps to be sure that it is the speakers that are cutting out.
The right speaker cuts out more often and at a lower volume than the
left speaker. Is this a normal or common trait of the ESL's. Is this a
fixable problem
Answer:
interesting that you should have this problem as I had the
very same one and just took care of it. The problem was diagnosed
and fixed by Daniels Audio, in Oak Park outside of Chicago. He
does a really TREMENDOUS job with these speakers- I'm basing this on
a full electrical upgrade that I just had completed.
In my case, and I suspect yours, the internal power supplies that
generate 5 kV from the line voltage had gone awry. One was putting
out 4 kV and the other even less, perhaps 3 kV. This can be fixed by
buying new boards from QUAD, or more cheaply simply replacing caps
and diodes on the relevant boards.
Why does this cause the speakers to cut out? Because in the
speakers, the signal goes through a transformer that steps it up a
factor of about 80 and it is this signal that appears on the panels.
In parallel with this, the signal passes through (if you have it) a
board that bleeds off current if the signal level gets too high. But
this reference is independent of the voltage across the speaker,
hence the apparent cutting out at not too great volume levels. I say
"if you have it" because this new clamp board is fitted only in newer
63s; it became available roughly 6 years ago I think. But your
problem really sounds like you've got it.
Now, my speakers play much loader and much more cleanly, without
clamping. Previously I had the speakers upgraded internally (mostly
new wiring) by Nick Gowan and that made a very large difference. But
this latest upgrade by Daniels is even more significant! My friend
heard the difference right away and immediately had his QUADs
upgraded and is equally ecstatic. Daniels has got a great line of
his own components (phonostage, preamp, speakers, cable, ...) yet he
has become entranced with the QUADs and is now designing structural
mods as well as a new power supply
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