ESL57 restoration finally started!

[cafe latte]

The dry season is here and we have just cleared out my workshop as I now have a couple of shipping containers for storage. My .308 is being rebarreld so my sundays are going to be free! I have decided to resore completely my ESL57s. When they were in use I already did the electronics side of things now it is the stators. I put them out of service when I noticed one side seemed a bit more quite. On removing a bass panel I managed to tear a dust cover (the unit that was quieter than the rest) and that is were it stopped. Today I removed the bass panels from that speaker and removed the dust covers and I think I know why that unit is quiet. The treble units are new in 1988 as is this bass unit but the rest of the units are far older, but looking through the stators all the other units have even coating in the diaphram execpt this one were it is only smered on in places at best (maybe 35% of the surface). Looking on the net this is not unusual so this panel needs a complete rebulid and as I am doing one I may as well do them all .
The best bit is I will probably sell them when they are finished.
here are the first pics..

The newer looking panel on the left is the one with the low output. I have removed the dust covers and the pic is when I was testing them without. I will post more detailed pics as I go, but it will only be when I have time so be patient


Regards
CL

[nuso]

Here's one well documented restoration of ESL57 for your inspiration:
Quad ESL 57 – Progress of refurbishment in pictures

[bauzace50]

cafe latte,

All the best wishes to you in your project!
It is a classic! May you have very happy results.

b50

[Teti83]

Hi, webpage DIY-HIFI.net is mine, I strongly recommend to buy necessary parts from One Thing Audio

to nuso: Zdar, jsem take z ceska

[cafe latte]

Hi, webpage DIY-HIFI.net is mine, I strongly recommend to buy necessary parts from One Thing Audio

to nuso: Zdar, jsem take z ceska

I bought most of what I needed over a year ago and I am just getting around to doing them now . I just need the pvc sticky tape for the edges and about 500 tiny screws and nut to replace all the rivets. The least fun bit will be removing all those rivets yawn..
Were do you buy the special tape?
Regards
CL

[Teti83]

What tape do you mean exactly, you mean double sided-tape or tape to seal panels / dust covers?

[cafe latte]

What tape do you mean exactly, you mean double sided-tape or tape to seal panels / dust covers?

Yes the tape to seal the panels, then you use it again for the dust covers,you can see the stuff I mean on the pic. It is not like normal tape though, it is stretchy like insulation tape.
Regards
CL

[cafe latte]

I just dug the box out with the film in for the diaphrams and dust covers and guess what is also in the box? Err a roll of special tape
So it looks like I am ready to start except I am a bit confused as which film is for what. There is a 3 micron film which is in the instruction as for the front high freq dust cover. There is 6 micron stuff which is for all the other dust covers and a slightly thicker slightly more yellow film which is not labelled which must be for a diaphram but just for bass or do I use the 6 micron for the treble
Regards
CL

[duficity]

Wow, latte, quite a project. But they should sound great when you are done. good luck.

[cafe latte]

Wow, latte, quite a project. But they should sound great when you are done. good luck.

I hope so, but I do plan to sell them, but I want to make them perfect first. This year I am hoping to get started on our extension that I have been putting off for a bit now. The new room will be a lounge which will be 40 feet long by 36 feet wide. My ATCs will say in the other room and I am planning to build these for the lounge http://www.eraudio.com.au/DIY_Speaker_K ... l_kit.html
, but they will not be allowed in the house unless the lounge is bigger . I have been vetoed on them before due to there size so I comprimised with the Wilmslow kit which do sound great. Anyway doing up the esl57s will be great practice, just need to pull my finger out and get going on the lounge which is the less fun bit.
Regards
CL

[pivot]

Look forward to your posts on this project. I always admire the sound of Quad 57s but the issues with amp matching and durablity make me gun-shy.

Sorta like W. C. Field's comments on marriage ("Women are like elephants - I like looking at them but would not want to own one.")

[cafe latte]

Look forward to your posts on this project. I always admire the sound of Quad 57s but the issues with amp matching and durablity make me gun-shy.

Sorta like W. C. Field's comments on marriage ("Women are like elephants - I like looking at them but would not want to own one.")

I like the quote .Apparently many of the Quads out there Have issues with sensitivity with either the EHT or leaking panels or have issues with dust ingression due to holes in the dust covers. The Panel I am doing first is a Bass panel that was replaced by Quad in the 80s so it should have been fine.... Then you take the panel apart and see that the technician must have been late for lunch or clock watching and wanted to go home on a Friday afternoon as maybe only 35% of the diaphram was covered with the conductive stuff. It was applied in wild streaks missing most of the bottom quarter of the panel which kind of explains why that panel was always a bit quite, I am amazed it worked at all personally, but apparently many are like this.
The good bit about the 1980s Quad service was the fact that new treble panels were fitted and the new at the time protection circuit. The treble panels will have been coated as poorly as the bass one, but at least the stators are not burned as may are as they have been protected since with the protection circuit so when I rebuild them properly along with the other panels (already done the EHT) they should sing and hopefully be reliable for someone for years to come.
Regards
CL

[cafe latte]

Here are a few pics so far, I am waiting on some new glue before I can continue but the most worrying bit ,opening the first panel is over without incident .
Here is the panel with the dust cover removed and frame being disconnected

Desoldered wires to pull through

Drilling the rivets out is the easiest wat to open a panel. The drill is almost the same size as the rivet. Apply no pressure to the drill just its own weight and drill the smallest side of the rivet. If the rivet starts to spin STOP and use wire cutters instead. Thake care big time with the corners as here you can apparently split the stator. I used cutters to do the corners as I did not want to risk it.

Removing the insulation tape from the edge

I drilled the center rivets first, but do not drill the three rivits were the conections go shown below or you will ruin the panel.The rivets do not go right through so they wont prevent you from splitting the stator.

This is the panel opened up and the diaphram exposed. The old Quad diaphrams were actually coated on both sides, when you consider this is both side coating you realise how poorly it has been done! The new coating stuff I got from ER Audio you only need to do it on one side and when my replacement glue arrives I will spray the conductive stuff on with an air brush to make sure it is even this time.

Regards
CL

[cafe latte]

Ok got going again, I finally had a bit of time today to get the next step done on the dismantelled stator. I ensured the stator was clean, then I laid an old shower door (stickers down ) I managed to get and cleaned it with meths also making sure there was no grit on it. I drew round the stator on the glass making sure not to get ink on the stator as some inks are conductive, I cut a piece of diaphram material and taped it in the corners to the glass with the ends of the tape folded over so I did not loose the ends .

Next starting at the long end using the spring gauge shown I pulled 800g Tacking both ends with a number of tags first and pulling one end, sticking doen, then the other until all tags are loaded to 800g. Basically you pull, then keeping 800g restick down the tape.

Next do the same with the long sides tacking all tags first and then tension starting from the middle, then lastily recheck the 4 corners, but with care as this is the easiest to tear.

Now to stick down one side of the stator to the film. First you run a thin bead of glue round the edge of the stator and using the pen mark on the class lower the stator onto the tensioned film then put heavy weights on it to ensure the stator sticks all round. Finally I found use for those Aus country and western records I bought in a job lot

Next a mad dash to find more weights as the records were not enough to get all the edges pressed down.

Lastily a perfectly tensioned diaphram ready to be coated with conductive coating. I actually did the next step today but misunderstood the instuction and put 3x too much coating on so I have had to redoo the whole thing .Anyway I am up to this point AGAIN so next chance I get I will put the coating on .

Regards
CL