Need help on Quad ESL 63

[paapt]

Hello,

I have been reconstructing the ESL 63 for some time now but I'm in a dead end. I could get one speaker to work properly (victory!) but not the other one (misery!). I have already tried a few things but with no result.

Let me try to describe the situation, to see if you can suggest any good idea:
- The speaker plays music but with lower level when compared with the other one
- the charge indicator looks good, with a blink every 2 seconds or so
- I cannot detect any distortion, or clicks and pops, the treble seems a bit recessed though
- I tested all 4 panels and they are all working
- I tried disconnecting each one individually, but with no result
- The electronics was working ok before, and I have changed panels from one speaker to the other with no obvious indication that one was faulting
- My last attempt was using tape around the sides of the panels to avoid leaks, this seems to have improved the situation, but not solving it

Any thing that I may be missing?

Many thanks for your help.

[Andersonix]

Originally Posted by paapt

- The electronics was working ok before, and I have changed panels from one speaker to the other with no obvious indication that one was faulting

Can you just clarify that all the panels work OK, but one side of the electronics is faulty?

[paapt]

All the panels and the electronics work OK, but the sound coming from one speaker is too low.

[harry_at]

Originally Posted by paapt

All the panels and the electronics work OK, but the sound coming from one speaker is too low.

Have you measured the output of the HV-supply?

This would be my first point with low volume and treble.

Harry

[JonasKarud]

Originally Posted by harry_at

Have you measured the output of the HV-supply?

This would be my first point with low volume and treble.

Harry

Measure the voltage over each rectifier diode, the voltage here is about 5250 divided by number of diodes. Use caution, HIGH VOLTAGE!!

It's a fairly common fault that one of the capacitors on the HV bias board
is "open". I always change all the caps and rectifiers on these boards when I refurbish Esl 63 speakers.

[chinsettawong]

Did you change the diaphragm? If yes, your coating on the diaphragm might not be good enough (too thin, resulting in too low conductivity). This would result in low sound level.

Wachara C.

[paapt]

Originally Posted by harry_at

Have you measured the output of the HV-supply?

This would be my first point with low volume and treble.

Harry

Unfortunately no. My multimeter does not go to the 5000V range.

[paapt]

Originally Posted by chinsettawong

Did you change the diaphragm? If yes, your coating on the diaphragm might not be good enough (too thin, resulting in too low conductivity). This would result in low sound level.

Wachara C.

I have redone everything, from re-glueing the stators to changing the diaphragms, etc. I have followed instructions from ER Audio.

You may have a good point though. The instructions on how to spread the coating are quite straightforward, but the results seem a bit too thin when compared with a panel redone by One Thing Audio that I have for benchmarking.

Can I spread the coating again, after cleaning with alcohol, or am I condemned to change the diaphragms? (the worst part is cleaning the glue, to say the truth). I would have to do it on the 4 panel.

[paapt]

Originally Posted by JonasKarud

Measure the voltage over each rectifier diode, the voltage here is about 5250 divided by number of diodes. Use caution, HIGH VOLTAGE!!

It's a fairly common fault that one of the capacitors on the HV bias board
is "open". I always change all the caps and rectifiers on these boards when I refurbish Esl 63 speakers.

On your opinion, what would be less expensive, buying a 5000V voltmeter or simply changing the diodes and caps?


I confess that I'm on the verge to simply give up. I had to go back to my previous speakers and they sometimes seem an upgrade compared with the 63. I know it sounds apocrypha, but I'm enjoying again high treble and some sound pressure...

[Speedskater]

It would be a "High Voltage Test Probe" connected to your meter. See below:

LUTRON HV-40: VARIOUS: Test, Tools & Supplies