Due to a house move I lost my quad esl 57 step up transformer. Does anyone have a broken ESL 57 speaker I could buy a step up transformer?
I have postal address in the Uk (My Parents) and Germany. If I had this part I would ship my old broken ESL's to Germany and try to get the lovely things running again.
Alternatively (because I have multiple quad 303's and 306's) I could go active on these speakers. Do people have suggestions for suppliers of treble and bass transformers that could do the job as well or better?
Quad no longer stock ESL 57 step up transformers, and the German supplier parts cost is too high considering the cost of broken quads in UK ebay (usually wont post even in UK).
I have postal address in the Uk (My Parents) and Germany. If I had this part I would ship my old broken ESL's to Germany and try to get the lovely things running again.
Alternatively (because I have multiple quad 303's and 306's) I could go active on these speakers. Do people have suggestions for suppliers of treble and bass transformers that could do the job as well or better?
Quad no longer stock ESL 57 step up transformers, and the German supplier parts cost is too high considering the cost of broken quads in UK ebay (usually wont post even in UK).
Dear Arend-Jan,
I have now received the transformer, thank you for your kind service.
Now I have to look at shipping the Quad ESL 57 speakers to Germany. I hope repairing my ESL 57's will be as pleasurable experience hearing them going again as I remembered from all these years ago, something that has made me think all magnetic coil speakers are inaccurate. The industrial 1950's radiator looks great even if the speakers do sound better without the metal grills if memory serves me right. I do remember them being big but light enough to move easily with a moderately convenient handle, which is important when you have limited space.
I have now received the transformer, thank you for your kind service.
Now I have to look at shipping the Quad ESL 57 speakers to Germany. I hope repairing my ESL 57's will be as pleasurable experience hearing them going again as I remembered from all these years ago, something that has made me think all magnetic coil speakers are inaccurate. The industrial 1950's radiator looks great even if the speakers do sound better without the metal grills if memory serves me right. I do remember them being big but light enough to move easily with a moderately convenient handle, which is important when you have limited space.
Thank you for the suggestion.
I have already tried it, and it is definitely true, but the bass output also goes down. Still I do feel that the Quad ESL 57 has magic in imaging and the presentation of acoustic music and not in its ability to play Dub reggae.
Here it is: http://www.quadesl.com/pdf/quad_schematic.pdf
Thus just one transformer with several windings.
ESL57 uses one transformer core, but has separate secondary windings for the midrange/tweeter closely coupled to the primary and an additional set of secondary windings on the other leg of the core to provide the additional voltage step up needed for the woofer panels with their larger D/S spacing.
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Lets see if I can attach this picture which is the inside view of a Quad ESL 57 step up transformer. I rebuilt thes some years ago. The outer cans were beat with some weld broken had them welded back together hammered them smooth filled the small dents with bondo and had them powder coated. Had access to a vacuum oven to remove and then replace the potting wax. They looked new again.
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As in everything audio , you will have to make that decision....
I have heard rebuilt and modded quads esl 57 , double stacked and triple stacked and the answer is yes, better than maggies for sure and on par with the best apogee's, including the full range or diva's models, yes very much competitive against those models...
The double stack ESL 57 is the best of the combination to me, the bass is very dependent on the type of stand, so be careful which stand you use. When setup right "they have power" plenty power.....
The triple stacked version is an overkill with power and the bass and you will need a large room for these to work well, but you would be astonished as to how powerful these rebuilt 57's can be , i have never heard fullrange ESL play with more power.... never ......
Here's a site with some pics of the quads I'm talking about, Wayne Piquet,is who did the work on my friends quads :
TripleQuads
I will try and get pictures of their actual setup next time .....
While we are there, one question about the internals of the transformer:
There are 3x 560pF ceramic capacitors inside for the crossover. As we know, ceramics are not the best for audio. Quad chose this type because of voltage tolerance for sure (they are 2kV or 5kV, I can't remember). I replaced them for lower voltage polypropylene in my units, and no ploblem so far, but I am a bit worrying of breakdown by high audio voltage. What would be a good sounding and reliable option?
There are 3x 560pF ceramic capacitors inside for the crossover. As we know, ceramics are not the best for audio. Quad chose this type because of voltage tolerance for sure (they are 2kV or 5kV, I can't remember). I replaced them for lower voltage polypropylene in my units, and no ploblem so far, but I am a bit worrying of breakdown by high audio voltage. What would be a good sounding and reliable option?
The step ratio feeding the tweeter-mid array is 87:1 according to Baxandall.
So the AC voltages seen by the 560pF capacitors will be substantially more than the VAC rating of most PP capacitors.
You might try the the 718P series of HV PP film caps made by SBE.
http://orangedrop.sbelectronics.com/images/PDFs/718p719p.pdf
I'd also recommend reading thru their presentation on HV film capacitors to understand why AC voltages stress film capacitors so much more then DC voltages, and why they fail over time.
http://orangedrop.sbelectronics.com/images/PDFs/APEC_2009_Seminar.pdf
Distributors for their capacitors can be found here:
SBE Inc. - Distributors - North-America
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Well I would assume that series capacitors designed to be higher in value then the load, so the voltage across is relatively small.
Corona is a nasty thing (used to make it for a purpose) - nevertheless I would doubt that capacitor designed for XXXVAC @ given frequency will fail before the specified time.
BTW do not use nonorganic caps for DC.
Alex
Hello alexberg,
The high pass network for the tweeter is formed by two 560pF capacitors feeding a 270Kohm load resistor in parallel with the tweeter panel capacitance. So, for frequencies below about 500Hz essentially the full output voltage of the step-up transformer will be seen across the 560pF capacitors.
The midrange panel does not have a load resistor in parallel with it, so the 560pF capacitor used in the midrange shelving circuit will not experience the full output voltage of the step-up transformer since, as you mentioned, the midrange panel capacitance is in series with it.
not all ceramic is "nasty"
at that size, V rating they could easily be NP0/C0G cermaic which is very good, better da than silver mica, competitive with some brands of polypro by Bob Pease' measurements Understand Capacitor Soakage to Optimize Analog Systems
at that size, V rating they could easily be NP0/C0G cermaic which is very good, better da than silver mica, competitive with some brands of polypro by Bob Pease' measurements Understand Capacitor Soakage to Optimize Analog Systems
I noticed something about the pictures you posted of repotting your ESL57 transformers.
I reposted the pic here as 1st attachment.
Your crossover board seems to be missing the 560pF used in the midrange shelving network.
Just curious...is this the way you found the crossovers? or did you remove the capacitor shown in the 2nd attachment with the red arrow pointing to it.
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