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Have to fix my Quad ESL 57
Have to fix my Quad ESL 57
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Old 12th September 2019, 07:02 PM   #81
lcsaszar is offline lcsaszar  Hungary
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But if I undestood you removed the mid/treble panel, and then the sensitivity was same as the other (working) unit. So the EHT is probably OK. I'd better concentrate to the mid/treble panel. It is riveted so you need to drill through the rivets in order to take it apart. I think you find a lot of instructions on the net. It is not an easy task, here is a nice example:

QUAD ESL 57 A little work on the loudspeaker
QUAD ESL 57 A little work on the loudspeaker "B"
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Old 14th September 2019, 10:07 PM   #82
legopart is offline legopart
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Do any solder can fit for this?
*though about using "Cardas Audio Soldering" (Heat vary easily but form really quality joints)
I started with this one (difficult to heat it good enough) A-BF 63-37 Tin Lead Rosin Core Solder Wire 1.1lbs(500g) for Welding Electrical Soldering DIY Repair Working 0.0236 Inches(0.6mm) - - Amazon.com

found that even shrinking tubes fits only up to 600V (the chines)

I got with the kit only 20AWG 6kV cable,
Think to order some 18AWG 10kV (or even 20kV) for the Bass panels if I will decide to replace them.

Last edited by legopart; 14th September 2019 at 10:35 PM.
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Old 17th September 2019, 12:51 PM   #83
legopart is offline legopart
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Originally Posted by johnsurnamerobinson View Post
BTW when i looked at eraudio site i noticed the coating solution is a SECRET formula.(see earlier post) and sold on the understanding the purchaser will not atempt to reverse engineer !!!
I really like this seller, he really helpful and really good man that supporting his items and upgrade his methods.
I bought some spare bottle of coating only for future failors and headphones fixing.
his compound really good,

but you have to remember to use some extra amount of this liquid because it remain some dirt that may stick to the membrane if you don't take the compound from the top (mixed with distilled water water 1:1).
this compound really strong and require only one sided coat.

about reverse engineer, It black colored liquid: meaning its contain coal or graphite (some conductive material)
and it drying really fast without option to remove any partials or dirt on it, it means that this compound contains some glue.
some ESL guides mention this fact about glue (wood glue?+soap (with some minerals)?, forget about it.)

Begin to fix my sr-202 and pretty like the result, the glue still not dried, but it good sound (I try it too early)
[will include some pictures letter as bonus because I cant fix the speakers so fast as I though]

Last edited by legopart; 17th September 2019 at 12:55 PM.
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Old 19th September 2019, 04:04 AM   #84
legopart is offline legopart
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Can someone reverse engineering this protective boards (QUAD ESL Widget)?

Click the image to open in full size.
Resistors Value is 0.39ohm 2-3w
the elements connected to the + signal in series, it means no parallel connections

Click the image to open in full size.
Resistors Value is 2.2ohm 2-3w
Capacitors, I sure that each 4 acting like 1 bipolar, 470uF 35v*2

it might look something like this
Click the image to open in full size.

I think that it might to work as Highpass filter, first level, for really low frequencies that could low the impedance of audio input to 0 and remain it with only less then 1ohm resistence.

*I begin some studies about the crossover methods
but at this point I forgot everything
same thing about electricity, complete only 2 years in university and quite to something else (programming).
2-Way Crossover Calculator / Designer
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Old 19th September 2019, 08:32 PM   #85
mattstat is offline mattstat
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Some discussion of it at link below. Sounds more like it is supposed to help the amplifier. If you want to protect the speaker, you should look for a different circuit.

OT's 'widget' schematics for the ESL57
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Old Yesterday, 04:32 AM   #86
legopart is offline legopart
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not so helpful, there is only some explaining for esl 63.
esl 63 board using maximum impedance in series of 3.3||3.3 ohm
esl 57 in 0.39||0.39 ohm
on low frequencies

wikipedia says something like this:
Its impedance is specified as '30-15 ohm in range 40Hz-8kHz falling off above 8kHz',[20] although another source states 'impedances are approximately 1.8 Ohms at 20 kHz but 60 Ohms at 150 Hz',[5] and its load is highly capacitive. It does not consume large amounts of power so much as it feeds it back to the amplifier in opposition at some points during each cycle. This is very demanding on amplifiers' stability.
more of this info QUAD ESL-57 ONE THING

some google: quad esl 57 impedance - Google Search

Click the image to open in full size.

so you gotta be ready to throw your amp after using this speakers.
and still even dynamic speakers using RMS settings for 1Hz that sets only some impedance.
speaker amps having some relay and protection board.

Last edited by legopart; Yesterday at 04:52 AM.
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Old Yesterday, 11:43 PM   #87
stokessd is offline stokessd  United States
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That graph looks familiar...

The quads are a reactive load, and you have to have an amp that is stable into a reactive load. But they are not overly hard to drive for any stable good quality amp design.

Simple tube amps, such as push-pull el-84 designs with simple dual triode gane and split load inverters.

Simple solid state amps such as the naim nait and such also can work very well. I use a modern version of the Nait (5i-2) in my shop and I play the orignal esl's with it all the time.

I'd argue that the original ESL's are more gentle on your amp than the modern quads when they clamp.

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