chinsettawong
Headphoneus Supremus
You should go and ask the experts here: https://www.diyaudio.com/forums/planars-and-exotics/
Whoa. Uhhhhh Do us a favor and be really careful with that stuff- 1 because these are nice rare speakers and 2 because they are biased with speaker voltages which are quite high and dangerous.What you recommend to do to fix old speakers that I trying to restore.
Qued esl 57
makes a lot of scratches noise on middle and high volumes.
though about:
1- check the bias voltage
2- check the electricity
3- recoat the diphrgm with antistatic spray
4- Try to open it and Strach the diaphragm better, or put another one.
may glade for any suggest where to start
thanks for any help =D
Look for any obvious holes and patch with scotch tape.What you recommend to do to fix old speakers that I trying to restore.
Qued esl 57
makes a lot of scratches noise on middle and high volumes.
though about:
1- check the bias voltage
2- check the electricity
3- recoat the diphrgm with antistatic spray
4- Try to open it and Strach the diaphragm better, or put another one.
may glade for any suggest where to start
thanks for any help =D
In the most bad case I can strech another cheap membrane for all of 6 speakers (Buy I dont know how to measure the streching force).Look for any obvious holes and patch with scotch tape.
Aside from that, if it's voltage related and again the voltages are dangerous with quad electrostats, then unless you have someone local who does refurbishments, then it's time to get rid of them sadly.
Okay, but seriously do be careful. These sorts of voltage multipliers "cockroft walton multipliers" are quite simple, but the actual parts themselves can't be measured in circuit if I remember correctly. Look for burnt diodes, they will be discolored and harder to read. Make sure all the capacitors are intact, no cracks. If the old membrane is loose, it will probably look loose. Under a light you should check the edges, see if the diaphragm is still taut. Check the center of the diaphragm by blowing on it gently. If it moves a lot it's probably too loose. I wouldn't patch any holes with tape as the above user suggested, but I would check for holes. You can definitely replace full diaphragms, but you will have to think of a clever way to mount the plastic in order to pre-stretch it.In the most bad case I can strech another cheap membrane for all of 6 speakers (Buy I dont know how to measure the streching force).
I can even glue the old membrane while streching it.
and I can try to remove one of dust membranes/filters and spray the original membrane, If they only dried from the first coating.
I not have any measure tools to measure the bias voltage of 6000v (the regular voltmeter works up to 1000v)
I dont know where to measure the bias
< the red part is covered by wax cube
I can test each capacitor and each diode.
I sure that they fine.
this data is from the company restoring book https://www.quadesl.com/origRefs/quad_book.pdf
And thank!, I'll be very carefull!
as I know screching sound may causes by:
- bad streching of the membrane or damaged membrane
- bad bias voltage
as chinsettawongone suggested, I will post the message in speakers furom too.
In the most bad case I can strech another cheap membrane for all of 6 speakers (Buy I dont know how to measure the streching force).
I can even glue the old membrane while streching it.
and I can try to remove one of dust membranes/filters and spray the original membrane, If they only dried from the first coating.
I not have any measure tools to measure the bias voltage of 6000v (the regular voltmeter works up to 1000v)
I dont know where to measure the bias
< the red part is covered by wax cube
I can test each capacitor and each diode.
I sure that they fine.
this data is from the company restoring book https://www.quadesl.com/origRefs/quad_book.pdf
And thank!, I'll be very carefull!
as I know screching sound may causes by:
- bad streching of the membrane or damaged membrane
- bad bias voltage
as chinsettawongone suggested, I will post the message in speakers furom too.
To reveal the diaphragm I have to remove the element first and then to cut the dust filter from the cornersI would do the easy stuff first. It looks dirty so try and clean it without damaging anything. Listen to the type of crackling you’re hearing. Check for bad capacitors etc.. I can’t imagine a bad bias is causing crackling. If there is no bias it will be very quiet or not work at all. It is also unlikely to be the voltage at the stators but you can measure it with a scope with a very low volume. Does the crackling change with different volumes? Is it possible to inspect the diaphram by removing the stators? how does it look? just don’t do anything complicated until you are confident something is the issue first. Start with the easy stuff first, and make as many observations as possible.
Do you have some guide to make some straching machine or where can I buy one ?Quad 57 isn’t that easy to fix. The stators are riveted together. If you want to remove them, you’ll need to use a drill press to drill all the rivets out. And then you’ll need to check if the stator surface is damaged. The stators are first coated with conductive paint and followed by insulation paints. If you need to remake the diaphragm, you’ll need to know what tension you need to get to first. You can buy a diaphragm repair kit from eraudio.com. They’ll tell you exactly what tension you need to achieve. Overall, it’ll take quite a lot of time to fix. And you need to do a lot of studies before you start fixing it. Don’t forget that you’re playing with extremely high and lethal voltage. Be very careful!
I tried but I can't find what I searching for inside this 200+ pagesWhy don’t you read through he threads in this forum just like everyone else has and like the other members have suggested half a dozen times before already?
eraudio.com not function anymore.Quad 57 isn’t that easy to fix. The stators are riveted together. If you want to remove them, you’ll need to use a drill press to drill all the rivets out. And then you’ll need to check if the stator surface is damaged. The stators are first coated with conductive paint and followed by insulation paints. If you need to remake the diaphragm, you’ll need to know what tension you need to get to first. You can buy a diaphragm repair kit from eraudio.com. They’ll tell you exactly what tension you need to achieve. Overall, it’ll take quite a lot of time to fix. And you need to do a lot of studies before you start fixing it. Don’t forget that you’re playing with extremely high and lethal voltage. Be very careful!