Hi,
Finally found the courage to open up my ESL-57’s.
(One of them had developed a low volume electrical buzzing sound coming from the back of the speaker where the power cord attaches…)
Been wanting to pull the grills off to see what kind of condition they are in as far as dust, signs of arching etc. Thing is, I’m not sure where to look or what to look for?
I suspect there are some parts that could/should be replaced also.
Any thoughts as far as what to be looking for, looking at, bring careful of would be greatly appreciated!
Thank you in advance!
Per
Finally found the courage to open up my ESL-57’s.
(One of them had developed a low volume electrical buzzing sound coming from the back of the speaker where the power cord attaches…)
Been wanting to pull the grills off to see what kind of condition they are in as far as dust, signs of arching etc. Thing is, I’m not sure where to look or what to look for?
I suspect there are some parts that could/should be replaced also.
Any thoughts as far as what to be looking for, looking at, bring careful of would be greatly appreciated!
Thank you in advance!
Per
Yeah, I know! It just looks that way 
But the solder joints are not very “solid”
And that dust isn’t good I suspect?
But that’s all for tonight. Don’t want to over do anything.
Patience and due diligence before I go any further
Not taking anything apart until much research has happened.
Hence this thread.
But the solder joints are not very “solid”
And that dust isn’t good I suspect?
But that’s all for tonight. Don’t want to over do anything.
Patience and due diligence before I go any further
Not taking anything apart until much research has happened.
Hence this thread.
Maybe you've already seen this, hopefully it helps if not ...
Quad Electrostatic Loudspeaker - Wikipedia
Electrostatic speakers: Quad ESL 57's: walk-through / inside them - YouTube
Quad Electrostatic Loudspeaker - Wikipedia
Electrostatic speakers: Quad ESL 57's: walk-through / inside them - YouTube
You can gently wipe off the dust with a soft brush and a vacuum cleaner ... you don't want to make a tear in the dust covers. If there are any smaller tears, you can apply som capton tape over it.
Then, with the covers secured, look for black burn marks through the back dust covers. Maybe you can spot some, maybe not.
With the dust gone, the AC transformer can be measured. Take care about the high voltages ... over 600V AC and 6kV DC to the bass panels. Treble voltage is about 2.5kV. You might not be able to measure it with a multimeter, but you can take an isolated tool and slowly approach panel voltage terminal, create an arc between panel voltage and ground. 6kV requires about 6mm or less distance. 2.5kV is about 2.5mm. Arcing at 2mm for bass panel indicates a bad supply.
If at all in doubt, don't proceed with this .. it is dangerous.
Then, with the covers secured, look for black burn marks through the back dust covers. Maybe you can spot some, maybe not.
With the dust gone, the AC transformer can be measured. Take care about the high voltages ... over 600V AC and 6kV DC to the bass panels. Treble voltage is about 2.5kV. You might not be able to measure it with a multimeter, but you can take an isolated tool and slowly approach panel voltage terminal, create an arc between panel voltage and ground. 6kV requires about 6mm or less distance. 2.5kV is about 2.5mm. Arcing at 2mm for bass panel indicates a bad supply.
If at all in doubt, don't proceed with this .. it is dangerous.
Cool, thanks!
Looks like tears in the dust covers have been taped up before.
Also looks like they were stored somewhere less than ideal from the water marks on the dust panels and the rust on the rear grills, although I don’t know if this is a common thing?
I think there is a high voltage probe available for my meter?
Checking voltage as a function of arc/mm is a new one. And the neighbors thought I was crazy arc welding on the porch at midnight in a thunderstorm
This may just confirm it
Looks like tears in the dust covers have been taped up before.
Also looks like they were stored somewhere less than ideal from the water marks on the dust panels and the rust on the rear grills, although I don’t know if this is a common thing?
I think there is a high voltage probe available for my meter?
Checking voltage as a function of arc/mm is a new one. And the neighbors thought I was crazy arc welding on the porch at midnight in a thunderstorm
This may just confirm it
I replace it with felt, about 1/16" thick wool. I make it smaller than the original burlap and horsehair pads by a touch since it's less permiable to the air, so I leave more area to leak by. I did some measurements to tune the size, but admittedly, they were pretty crude back when I did them.
Sheldon
Sheldon
I don't recommend using a vacuum cleaner for removing the dust. I used cosmetic pads soaked with isopropanol. Gently wipe off all dust, especially at the terminals. You can use a small brush too.
Take care of the HV, the panels can keep the charge for a long time. If you want to be safe, discharge them to GND with an insulated multimeter probe wire.
In general, you don't need to measure the HV. If you really want, use a 10Gohms probe, which is not easy to find, and is not worth to buy for only this measurement IMO. If the left, center, right panels sound loud, the dust covers are not torn, and there are no visible burn spots, they are good.
Take care of the HV, the panels can keep the charge for a long time. If you want to be safe, discharge them to GND with an insulated multimeter probe wire.
In general, you don't need to measure the HV. If you really want, use a 10Gohms probe, which is not easy to find, and is not worth to buy for only this measurement IMO. If the left, center, right panels sound loud, the dust covers are not torn, and there are no visible burn spots, they are good.
Thanks!
Have not removed anything from them as of yet - other than the covers. I’ve seen people use vacuum cleaners to remove the dust. I have fears of the covers vanishing into the vacuum in the same way curtains gat sucked into them in comedies
For now, I’m just going to clean them, replace the rear damping material and clean up the solder joints. Then I’ll plug it back in and listen to it.
If it’s still “sizzling”, I’ll replace the EHT board and while I’m at it, add clamp boards.
Panels all look good, dust covers are intact with the odd bit of cello tape
Have not removed anything from them as of yet - other than the covers. I’ve seen people use vacuum cleaners to remove the dust. I have fears of the covers vanishing into the vacuum in the same way curtains gat sucked into them in comedies
For now, I’m just going to clean them, replace the rear damping material and clean up the solder joints. Then I’ll plug it back in and listen to it.
If it’s still “sizzling”, I’ll replace the EHT board and while I’m at it, add clamp boards.
Panels all look good, dust covers are intact with the odd bit of cello tape