Quad ESL 57 – crossover/phase issue?

Hello, I annotated the photo of your trafo bottom. Please check if each wire goes where it should. And where does the thick red wire go from the RT turret? (RB = rear bass, FB = front bass, RM = rear middle, FM = front middle, RT = rear treble, FT = front treble)
Hey, I can answer my own question: OTA installed a protection board at the left. The red wire goes there from the Rear Treble turret, the other wire is not visible, but should go from the Front Treble directly. Only you can check it.
 
The red wire goes there from the Rear Treble turret, the other wire is not visible, but should go from the Front Treble directly. Only you can check it.
Hello, the other red wire from the clamp board goes to the next terminal to the right of RT as marked in your photo. Not direct to the treble FT.

Regards, to the markings you made on the crossover circuit and thank you for that. The bass connections were correct until I reversed them to put the bass panels in phase with my right-hand speaker. So perhaps that speaker should have been changed? With regards to the tweeter connections you can see from the photo that it is not possible to see if they are wired correctly.

It's time now for me to check the wiring of my right-hand speaker.

I assume that you are following the correspondence I'm having with others on this Forum. This is all new for me!

Rodney UK
 

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Quad was very consistent with wire color in these speakers; brown to the treble panel center section, and blue to the outer sections (in parallel). This is tragic, because they are identical colored wires, so it's super easy to get phase screwed up. They should have made those 4 distinct colors. The ground wire is black and thin. The bass panel wiring is thick, and the rear stator is a thick white wire, and the front stator is a thick black wire. The treble panel has a thin red wire to the HV supply, and the bass panels use a thick red wire to the HV supply.
I am very confused. Remember I changed the bass wires around on my left speaker so that it "appeared" in phase with the right speaker. But actually the bass panels were already wired correctly. I have checked the wiring on my right speaker and it all looks good. As you have pointed out, it is very easy to wire the treble panels the wrong way round. I thought the best thing now is to do the pulse test first described to me by Wout31. First the bass panels and then the treble panels. This should clearly show if they are in phase with each other.

VERY IMPORTANT To do this test I need to charge them up! Are there any high voltages on the audio transformer to worry about when I do the soldering?

Many thanks Rodney.
 

Zung

Member
2005-04-30 7:30 pm
Geneva
Yes you do.

But before that, use the opportunity to visually check the wiring: from your pic "Tweeter connectons", it's very easy to see which wire is front, and which is back. I use a sharpie to mark the wire transformer side, it may take a few wiggles.

Also, check all other wirings for consistency.

1641734860811.png
 
it's very easy to see which wire is front, and which is back.
I checked both brown and blue wires on both Quads very carefully and they are correctly wired. It is only the bass panel wires on my left speaker that I changed around to make the speakers sound in-phase when the red & black's are connected correctly to the amp.
I checked my colour coded speaker wiring to the amp also. I use the OTA Wiget box but that does not affect the polarity as far as I know.
Before buying the 303, I was using a Nad M22 amp, so Steve Williams suggested using one of his Wigets for safety which he kindly included in the Quad purchase.

I can't imagine that the 303 speaker outputs have been wired incorrectly?

So maybe now is the time to do the pulse test on each of my speakers. Bass and tweeters separately on each speaker.

What about the high voltage!!!!
 
I checked both brown and blue wires on both Quads very carefully and they are correctly wired. It is only the bass panel wires on my left speaker that I changed around to make the speakers sound in-phase when the red & black's are connected correctly to the amp.
I checked my colour coded speaker wiring to the amp also. I use the OTA Wiget box but that does not affect the polarity as far as I know.
Before buying the 303, I was using a Nad M22 amp, so Steve Williams suggested using one of his Wigets for safety which he kindly included in the Quad purchase.

I can't imagine that the 303 speaker outputs have been wired incorrectly?

So maybe now is the time to do the pulse test on each of my speakers. Bass and tweeters separately on each speaker.

What about the high voltage!!!!

I'm getting a bit confused here. You swapped your bass wiring in the left speaker to make them sound in phase, but are the bass panels in the left speaker now out of phase with the tweeter in that same speaker? IE is the bass panel wiring as it is on my wiring diagram, and in the picture by Zung? you want the "white" wire in Zungs picture to go to the rear terminal (left) on each bass panel.

I have no idea what the "widget" is; if it were me, I would throw that crap out immediately. Also add a treble panel clamp circuit while you are in there. In your picture of the treble panel wiring above (post 62), it appears that there are a pair of high voltage wires spliced together, that's bizarre and there is no reason to do that. Who knows what other delights are hidden inside those panels...

WRT the high voltage: Don't put your tongue on it... Other than that, you'll be fine.

At the end of the day, this is really a simple problem, that is getting all blown out of proportion. Open both speaker backs, unscrew the audio transformers and flip them over so you can see the wires. Trace them all out. Find the mis-wiring. Fix the one that doesn't match the wiring diagrams provided above by several of us. Reassemble and enjoy.

Sheldon
 
You swapped your bass wiring in the left speaker to make them sound in phase, but are the bass panels in the left speaker now out of phase with the tweeter in that same speaker?
Could be, and that is why I want to check this out with REW.

Yes Sheldon, I agree, it is getting a bit involved/complicated and everyone must be tired out including me:D As far as I can see, both speakers are wired up correctly. I will reverser my wiring to the bass panels on the left speaker so that all wiring is as it should be and carry on as before.

Unfortunately, I haven't addressed why the left speaker is down in level compared to the right speaker and with a less flat response. Perhaps I will have to live with that.

But never mind. I am very grateful for your time and help. That also goes to the other participants who have been trying to sort things out for me.

Happy New Year to you all, Rodney.
 
Not good.
If there was someone else in England with the knowhow in restoring Quad 57's I would be tempted to get them checked over.

I checked the panels separately on the left speaker for phasing and with the bass panel wired back to where it was, both bass and tweeter are in phase.. Oh. I'm still alive to tell the story:D

I must try another amplifier to check whether the 303 has been wired incorrectly.
 

rayma

Member
2011-04-29 8:37 pm
OT, but I can't resist: here's one the delights I found in a bass panel I bought off eBay, advertised as "serviced, new wiring, tested. perfect..., in excellent condition".
As an extra bonus, they left a blob of cotton between the stator and the dust cover!!!
Wow, can you provide a link to that ebay listing so I can be sure to avoid it?
We should know about that.
 
The forign crud in the speaker isn't great, but it's super easy to have something trapped somewhere in the original quads. Those wooden dust cover frames are often quite roughly cut wood and can easily grab hairs, bits of paper towel, etc. As long as the crud isn't conductive, the speakers are surprisingly forgiving. Don't forget they weren't made in a cleanroom, they were made in a pre-war style factory and cranked out as cheaply as possible. So I wouldn't be too hard on the rebuilder for an occasional screwup, what matters is that the rebuilder quickly and crisply rectifies their problems without a lot of bullsh1t. This tread exists because this rebuilder didn't fix his screwup after a second try.

just my $0.02

Sheldon
 
just my $0.02
UPDATE I contacted Steven of OTA regarding the out of phase speaker, despite the wiring being correct. His reply was:

"Just swap the speaker sockets over on the
one that's out of phase.
It sounds like one of the transformer windings
is different"

He further goes on to say:

"No effect on sound quality , we've had a few
over the years"

Perhaps the audio transformer is an early one when MONO was in common use and Quad didn't pay much attention to polarity?

Rodney
 

wout31

Member
2012-02-13 7:59 pm
Limburg
If I read correctly, you have determined that even if you reverse phase on one speaker your "problem" remains.
Next you have determined that all panels are properly wired. So why keep repeating those words: out of phase.

I see different age (building years) panels. Different naming Otec and Otec-B. Looks like a 2 year difference.
So it looks like this is not the original configuration of the initial rebuild of the speakers, where I would assume all panels are from these same series.
Makes you wonder why. Were there issues in an earlier stage? Who has worked on the speakers? Do these panels sound / act the same? Are they different in aging? Different in build? Again, I assume if you go from model A to model B there is a change that gave reason to the model naming change.

What I'm also wondering:
How different are these Otec panels compared to the original panels? What are they, PCB based?
How do these panels interact with other components or influence the sound of the system?
 

Zung

Member
2005-04-30 7:30 pm
Geneva
I see different age (building years) panels. Different naming Otec and Otec-B...

Good point, wout31!
Why do ESL57 refurbishers HAVE to be sloppy?
With regards to the phasing of the transformer, you may want to try connecting a pulse generator (the one in your phone will do) to the speaker terminals and see what comes out of the secondary's, best with a scope and a 10:1 probe.
 
Why do ESL57 refurbishers HAVE to be sloppy?
Simple, because most people don't want to pay for a good rebuild.
General idea is that you can buy "the best speakers in the world" for a few hundred $, € (or other currency) and they are GREAT.
If not great immediately, just dabble a little DIY and then they are GREAT.

Doing good work on these very old speakers involves a lot of time, involvement, knowledge, patience etc.
Because of it's age it is not a simple speaker to work on at all.
 
If I read correctly, you have determined that even if you reverse phase on one speaker your "problem" remains.
Hello, I know that you are trying to help me and I do appreciate your time. At 76 I do get a bit confused at times!

To answer your question above, No, there is not a phase problem when my left speaker connection is inverted.

Amongst my original concerns were:

1, I have to listen to the speakers with one of them connected in reverse.
2, Sound level on left speaker down. I realise now that is partly due to my left ear being less sensitive.
3, When both speakers are measures together there seems to be some cancellation at certain frequencies.

This morning I did some more measurements at listening position. In my opinion, there is something odd on going on!

I can't understand why I am now getting a big dip around 8Kh. My previous measurements didn't have the dip!!! I never touched the tweeter wires.

I hope that my REW attachment will work!

Rodney.
 

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  • REW measurements 12.1.22.mdat
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wout31

Member
2012-02-13 7:59 pm
Limburg
Rodney, you can take measurements like this until .................. but it will most likely not bring you any closer to a solution.
If there is a imbalance in the speaker you have to take it apart to do electrical measurements on separate panels, EHT and transformers and maybe, if you have enough experience, that will shine a light on what is wrong.
  • Panel leaking
  • Part / total of the panels drawing too much power for the EHT, resulting in voltage drop
  • Construction problem in any of the panels
Are just a few of my thought where I would start looking.

Regarding your measurements. Some are taken at listening position and in that case a lot more happens. Simple said: Your room gets in the way.
No room (read that again, none!) is even close to prefect and there will be reflections, standing waves, comb effects on your listening position.
A slight shift in placement of the speaker, moving a couch, closing the curtains can make a difference.
 
Rodney, you can take measurements like this until .................. but it will most likely not bring you any closer to a solution.
If there is a imbalance in the speaker you have to take it apart to do electrical measurements on separate panels, EHT and transformers and maybe, if you have enough experience, that will shine a light on what is wrong.
Thank you vout31 for looking at my measurements . Unfortunately, all those checks you mentioned are beyond my scope.

I don't think sending them back to OTA will be much point. Unfortunately, I don't think there is anyone else in the UK that repairs these speakers commercially. I could look for another pair on ebay but who knows whether they will be any better.

I am still getting much enjoyment using them.

It seems that I have come to the end of the road :cry:

Regards, Rodney
 
Why do ESL57 refurbishers HAVE to be sloppy?
Not everybody is.

This is quite frustrating, I need like an hour with them and some simple test equipment to get to the bottom of the issue. But my arms aren't quite long enough. I would have been to ireland and the UK at least twice if the pandemic hadn't happened too.

I don't know anything about the OTA panels, they look VERY unstock. That can be fine, because the stock panels are no great shakes. But I can believe that they might perform differently. And maybe they perform differently over time or between generations.

I am very willing to help out however I can, feel free to ask questions etc. I'm always availalbe, but I'm not sure how I can help at the moment.

Sheldon