Quad ESL57 - Treble reduced radically?

[candersson]

I would not use 12um for the treble panels. 3um would be more appropriate.

But, it is not an easy job to dismantle the panel and fit new film with good coating.

Regarding the EHT ... it is usually the diodes that are faulty. Only replace parts in the EHT if the voltages are low (without load, disconnected from the panels).

 

[stokessd]

I use 6uM film for Quad 57 treble panel diaphragms.


ER Audio has rebuild kits that will provide everything you need to rebuild a set of quads.

Quad 57 Repair Kit


Sheldon

 

[wolfiesn]

All I can say is a huge THANK YOU to all who responded - what a forum, and what a group!

Sheldon, I downloaded your (extraordinary) guide; this is a major achievement, and I congratulate you heartily. It is hard to see how this piece of work could be in
any way improved. I read it slowly and carefully, as it deserved, and it gave me some courage to go forward.

As I have only the most rudimentary electronic skills I proceeded extremely slowly in the analysis: try as I might I could find absolutely no signs of any arc-damage on the treble panel. So I took a small risk (remembering my lack of skills...)
I decided it might be the EHT panels: they were of different vintages anyways, so I figured I only had a little to lose.
One thing led to another, as it inevitably does, and I decided to re-wire the three panels at the same time.


Result - back in HEAVEN!


The panels took a little time to charge (about fifteen minutes), and again the sound is breathtaking. Actually, what sound? With the 57s it's just about the music!

I'm glad to see the Maggies (12QR) go: with no disrespect to them, the company, and certainly not the owners of the same, they're simply not the same experience.

BTW, just picked up a mint Proton D1200: stable and powerful.....and big green meters <grin> The speakers certainly seem very happy with their new diet.


Again, a huge thank you to all: it's a wonderful feeling to know there are kindred spirits - who give their help so freely!

 

[candersson]

It feels really good to be able to help with these great speakers. There are different ways how to fix certain problems - and this is the good thing about forums - everyone gets a chance to tell their story.

I also used Sheldons guide to learn about the ESL:s before I tried to fix them. Very good work!

Happy listening!

 

[stokessd]

I've got several hours of video detailing my current rebuilding techniques for both the original Quad ESL's and the ESL 63's. I need to fire up Final Cut and edit it into something for public consumption.

Stay tuned.

Sheldon

 

[woodturner-fran]

Will definitely stay tuned for that Sheldon....

 

[stokessd]

Will definitely stay tuned for that Sheldon....

Thanks Fran, you live in an amazingly great part of the world.


Sheldon

 

[woodturner-fran]

Thanks - you too!

 

[geraldfryjr]

I've got several hours of video detailing my current rebuilding techniques for both the original Quad ESL's and the ESL 63's. I need to fire up Final Cut and edit it into something for public consumption.

Stay tuned.

Sheldon

Sweet, It was your original videos that finaly got me going on building esl's in the first place.

Thanks very much Sheldon. jer

 

[sheep]

Where are the videos?

 

[Soundexcel]

Hi All.

I have the same problem as the topic starter:

One of my ESL 57's has a reduced output.

First i though it was the EHT unit.
I rebuild both power supply's an they work like a charm.
Unfortunately this didn't solve the problem. Still one panel has a much lower output.

I measured the voltage on the power supply. When the the treble panel is connected, the voltage drops to 225V instead of 1200V.

My first conclusion: the problem is in the treble panel.

I measured the resistance of the treble panel:
Both blue and brown measure with one multimeter nothing, with the other between 1,5Mohm and 2,5Mohm.
The capacitance is 160pF and 280pF.

I Also measured the bass panels: no resistance and around 550pF.

i am confused....

Does anybody know what the issue could be?

 

[arend-jan]

If the voltage drops when you hook up the treble panel to the power supply then the logical conclusion would be that it has a short between the charge ring and the stators. So between the red wire and one of the blue/brown wires. Did you measure those resistances?

 

[Soundexcel]

Yes i did, al of them have a to hi resistance to measure

 

[stokessd]

Here's a quick and dirty trick to see where the short lies. Unbolt your audio transformer and flip it over in place (assuming your treble leads are long enough). Unsolder your blue and brown treble wires one at a time, and watch your HV. Also if you don't have a HV probe, hthen you can just bring your unsoldered wire to the terminal slowly. The non-shorted wires will produce a small arc just before touching. The bad section will arc much more loudly and farther away.

Sheldon

 

[Soundexcel]

Thanks for the tip. I will check that today.

I double checked and the problem lies in the treble panel.
When the treble panel is disconected from the power supply, the low panels preform excelent.

This will probable end up in a revision of the treble panel

 

[Soundexcel]

So.

I did the suggested test, and with result:

When the bleu wire is desoldered from connector 12 (the bottom connection point with the resistor and capacitor parallel) the voltage is around 1200V as it should be.

I measured the components and windings of the audio transformer and they look ok.

conclusion, bad high section. Time for some refurbishment, or am i missing something?

 

[arend-jan]

I'm willing to put money on it that your treble panel has arced somewhere. Perhaps if you look very carefully (peep through all the holes from all angles, using a torch) or perhaps it's not visible from the outside.

 

[Soundexcel]

I am going dismantle the panels next week an the plan is to get them refurbished next month (i don't have the time, and gear to do it wright).

The other panel (the working one) has a black spot on the dust cover, so this one has a clear arcing trace.

I will get both panels refurbished, also keeping the matching of the two panels in mind.

Thanks for all the help.

 

[koyaanisqatsi]

hello there in diy land.... i'm sitting here listening to my new/old Radford sta15 valve amp (original/unmolested/good condition) and Quad esl57(last serviced by quad in 87), just delivered to my door for £750 all in.... wonderful sound, plenty of bass (i'm used to PMC tb1 monitors/musical fidelity a3 amp). whats all the nonsense... i.e. bass light, small sweet spot, need large room?

i've got the volume set at the loud side of just right (so maybe a little louder would be needed sometimes. but that little bit louder is where one speaker starts to break down, slight crackle/pop... then a rasping clicking (seemingly a bass panel.. cos bass heavy passage brought it out).. for now i'll keep the volume at the perfectly usable volume where the sound/bass/treble are all fine/great really.

any comments?...

i know they need work... but they should be ok for a while ? they sound so good/even as they are.

 

[koyaanisqatsi]

done a bit of reading and....these symptoms are more like treble panel?