Update on the topic: I've managed to source 3 BASS panels for only 30 EUR/panel, the dustcovers were intact on two, and panels are in good state optically.
I don't know if my analogy is good, but I still can see the conductive nylon coating on the saran through the holes, so I will pick the most matching two of 3, and use these as a substitution of the panels those are more or less faulty or maybe just way too old.
Reason:
Next to the above mentioned symptomps of those BASS panels inside the speaker, I found out with a tone generator, that the panels produce few dBs less around 80-100Hz, and can't go lower than 60Hz as the healthy side could easily, despite those are original panels, too.
I will have to tidy up them a bit, and redo the dustcovers, and I will do the swap
I don't know if my analogy is good, but I still can see the conductive nylon coating on the saran through the holes, so I will pick the most matching two of 3, and use these as a substitution of the panels those are more or less faulty or maybe just way too old.
Reason:
Next to the above mentioned symptomps of those BASS panels inside the speaker, I found out with a tone generator, that the panels produce few dBs less around 80-100Hz, and can't go lower than 60Hz as the healthy side could easily, despite those are original panels, too.
I will have to tidy up them a bit, and redo the dustcovers, and I will do the swap
The iron parts (that connected to the ground) connected directly to EHT negeative.
I think that new technology will use some capacitor (or resistor) between the EHT negeative and the ground.
about you'r problem,
first disconnect, discharge and then check first the tension.
next you can connect the panels one by one to check which one having this issue.
really great work you done on your speakers.
thanks for sharing.
hope that you will success to fix this speaker.
Well, it turned out, that the panels were faulty... I've finished the swap. The problem wasn't in the transformer box or the EHT... These recently bought original panels had enough coating on the membrane that could charge up as they should and give an unbelivable strong and stiff bass. Except that the PE cellotape do not stick too well on the front of the panels, the procedure went well without any unwanted event. I am a happy man now. I have 3 bass and 2 trebles spares at the moment, so It's time for some experimenting...maybe to try out making a membrane for these, or just sell them to a hobbyst
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My speakers sound bass annoying.
I planning to take the risk and restore them by myself.
my parts is still the original Quad panels (from 80s+)
Good to know that you fix them.
*about sell them, will be helpfull for anyone who searching one.
*about experimenting/restoring. could be annoying because you have fixed pair of speakers, that its bad idea to mess and open them only for the experiment.
and still could be nice to have some replacement parts for the tweeter.
you need only 1 bass panel and you can build new pair of Quad 57 speakers
I always though about it, if you planning on second pair, why not to use the same EHT and the same crossover for 2 speakers.
Good to know that you finish the restoring,
enjoy!
addition question,
What amp do you use for this speakers?
I planning to take the risk and restore them by myself.
my parts is still the original Quad panels (from 80s+)
Good to know that you fix them.
*about sell them, will be helpfull for anyone who searching one.
*about experimenting/restoring. could be annoying because you have fixed pair of speakers, that its bad idea to mess and open them only for the experiment.
and still could be nice to have some replacement parts for the tweeter.
you need only 1 bass panel and you can build new pair of Quad 57 speakers
I always though about it, if you planning on second pair, why not to use the same EHT and the same crossover for 2 speakers.
Good to know that you finish the restoring,
enjoy!
addition question,
What amp do you use for this speakers?
The two trebles I have are in good condition, so I wouldnt' even touch them, but the recently dismantled basses are a good donor, so worth dismantling them. I read at some chinese forum, that you are able to recoat the membranes simply using some kind of shower gel that contains a specific material, but I am sure that the membrane itself lost it's qualities that suits the factory specs (resonant frequency)
I use an american Dynaco ST 70 for driving them, it does 35W continuous per channel.
I use an american Dynaco ST 70 for driving them, it does 35W continuous per channel.
look
I tried to restore my Stax lambda normal headphones after they broken,
and fail!
loose even pair of Stax sr-202 because mess with it
ESH is really hard issue to deal with.
From this forum they suggest to use some Antistatic-spray and cheap Chinese Mylar that useless and I don't like
even good glue I failed to find
My DIY electrostatic headphones | Page 245 | Headphone Reviews and Discussion - Head-Fi.org
after bought this fail Quad Esl 57 speakers and bought the repair kit from here Quad 57 Repair Kit
the membrane glue is pretty good and the coating liquid is pretty good,
still fail to restore my headphones.
You can order separate items from here
Step Up Transformer
also, by this old guide The Quad ESL - Treble Panel
*also has some for the bass panels
it says on the begin
in other words, after 10 years, the original membrane is useless
because loose of tension and loss of coating.
I tried to restore my Stax lambda normal headphones after they broken,
and fail!
loose even pair of Stax sr-202 because mess with it
ESH is really hard issue to deal with.
From this forum they suggest to use some Antistatic-spray and cheap Chinese Mylar that useless and I don't like
even good glue I failed to find
My DIY electrostatic headphones | Page 245 | Headphone Reviews and Discussion - Head-Fi.org
after bought this fail Quad Esl 57 speakers and bought the repair kit from here Quad 57 Repair Kit
the membrane glue is pretty good and the coating liquid is pretty good,
still fail to restore my headphones.
You can order separate items from here
Step Up Transformer
also, by this old guide The Quad ESL - Treble Panel
*also has some for the bass panels
it says on the begin
in other words, after 10 years, the original membrane is useless
because loose of tension and loss of coating.
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How did you fail with the repairs of the Lambda? ( As far as I know, those driver units are enclosed with epoxy -the dustcover-stator-diaphragm-stator-dustcover sandwitch glued around the edge-, so they are very hard to open it up without damaging the rings or the stator itself ...)
I don't think that the original panels are useless. Despite, I haven't heard a factory new or newly refurbed panel, originals, those are in good state or "health" are sound so delicate... I think the health of a panel mainly depends on how was the speaker been stored for years. If it was used someplace where the climate is humid, or was long term exposed to direct sunlight, or had blown dustcovers for years, the chances are high that those are way out of the specs.
That is my opinion, but who knows
I don't think that the original panels are useless. Despite, I haven't heard a factory new or newly refurbed panel, originals, those are in good state or "health" are sound so delicate... I think the health of a panel mainly depends on how was the speaker been stored for years. If it was used someplace where the climate is humid, or was long term exposed to direct sunlight, or had blown dustcovers for years, the chances are high that those are way out of the specs.
That is my opinion, but who knows
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