One Thing Audio
Quad
Instructions, ESL 63, Refurbishing

Table of Content

Warning
Soldering
Removal of the top panel
down Sketch
Removal of the upper mid, lower mid and bottom bass

Warning

WARNING: Electrostatic loudspeakers can remain charged up for anything up to two hours after being unplugged from the mains. If possible, leave them overnight to discharge. But if a 'quick' discharge is required, short the HT (any connection on the HT line central rear) down to speaker chasis (ie. metal frame or spring grille contacts, bottom of speaker). NEVER work on a speaker while it is plugged into an amplifier, even if the amplifier is assumed to be switched off. Basic electronic skills and technical competence are assumed for anyone reading these notes.

Soldering

With a long history of removing and refitting ESL 63 panels into their frames, we are well aware of the snags and pitfalls that can beset the enterprising, but unwary, panel fitter! Broken or split electrodes (the perforated plates) or a split around the periphery of the diaphragm are fairly common due to 'slipping' with a screwdriver, but by far the commonest hazard is solder splashes welding themselves to the Mylar diaphragm. This will quickly shut the speaker down when any volume is applied as the speaker's sensitive RF 'sniffer' circuitry registers a fault

ALWAYS reinstall panels with the 63 speaker frame standing vertically, NEVER with the speaker lying down. This way, if solder should fall it will stick to the louvre only and can be flicked away with a Stanley blade or similar. Also, always use a cloth or towel over the bottom delay-line electronics and pulled down stocking (secure it to the upright struts with fold back clips, clothes' pegs etc) - this way, if solder should fall it won't lodge itself on the bottom delay-line board or stocking.

When we supply rebuilt 63 panels, we will have removed any excess solder from the panel's terminal clips to minimise the risk of splashing. Most 'slips' with a soldering iron are caused by worn, contaminated and insufficiently "tinned' solder tips. The user becomes impatient because the solder is reluctant to melt, and attempts to transfer more heat from the tip by applying pressure. WRONG - and hazardous! The soldering iron is about to slip and destroy your precious diaphragm! Always use the very minimum of solder to do the job and ALWAYS use a new (or newish) well-tinned tip. If the solder doesn't want to melt immediately, don't apply more pressure to the joint - take the iron away, clean the tip, re-tin it and try again.

If you find it is difficult to keep the wire pressed against the panel's solder clip, apply a small amount of solder flux (available from Farnell, Radiospares etc) to the clips first. Then, holding the wire against the clip with a pair of pointed-nose pliers, melt a SMALL amount of solder onto the iron's tip and carry it to the flux-prepared solder clip. The small amount of solder carried on the iron's tip should be sufficient to make a good soldered joint.

Good luck! Work slowly and methodically, and DON'T rush the job. Try to make sure the solder goes only where it is needed - ON THE SOLDERED JOINT!

Removal of the top panel

  1. Remove wooden top. (Press down firmly and slide to the right)
  2. ‘Unpick’ the stocking from the Velcro. Roll the stocking down the speaker.
  3. Remove the ‘duck’ tape from the top and bottom of the speaker (this will need to be replaced – available from any DIY store).
  4. Both front & rear grilles will now need to be ‘eased’ out of their side rails together with their ‘duck’ tape edging. With a flat screwdriver, ease forward a top corner first, then ‘coax’ the grille out of its rail. Note: this sometimes distorts the grille at the edge, but it can easily be straightened out afterwards.
  5. With grilles removed, remove both front & rear dust covers. Again, with a flat screwdriver, first ease forward a top corner. Then slide forefingers down behind it to release it from its rail. Repeat this action with the other side of the dust cover so that both left & right edges are freed. Then ease off top and bottom (this is usually possible by just gently pulling forward – but take care; the 3 micron film is very easily damaged).
  6. The speaker’s top plastic plate should now be removed, but first draw an arrow on it with felt-tip pointing to the FRONT of the speaker. When re-fitting the plate, this orientation MUST be observed. Remove the 8 countersunk self-tap screws, noting that the 4 central screws supporting the vertical aluminium supports ARE LONGER. Don’t mix them up. Lift off the top plate together with the plastic ‘hood’ which sits underneath it – DO NOT forget to return this hood prior to re-fitting the top.
    IMPORTANT NOTE: When the top is lifted off, it invariably brings with it one or both of the neopreme 'caps' which sit on top of the two panel-supporting aluminium struts. Even if they stay in place, it is recommended that the caps be lifted off and a blob of contact adhesive applied to the caps before returning them to the supporting struts. These caps insert into an indent in the plastic top (two oblong slots at either side) and it is best to examine these beforehand to see how they engage into the plastic moulding when the time comes to reassemble the plate.
  7. REMOVING THE TOP PANEL: Unsolder the two audio links front left & right at the uppermost solder terminals only (ie. the ones soldered to the top panel’s terminals, and bend the wire links forward). Do the same for the rear of the panel, but additionally unsolder the centre HT wire link from its terminal on the top panel.
  8. Remove the four self-tap screws supporting the panel, and lift the panel upwards and out of the speaker frame. Fit a new panel in reverse order of the above.

NOTE: Some early production speakers (prior to S/No 11601) use soldered spring clips in place of the wire links. It is recommended that the solder be carefully drawn off with a good solder-sucker until the clips part. The later-type wire links should then be substituted when a new panel is fitted.

Sketch top

sketch

REAR aspect of speaker.  FRONT aspect identical, but without the central HT line.

Removal of the upper mid, lower mid and bottom bass

For removal of the three lower panels, removal of the top plastic plate will not aid this operation. Instead, it is necessary to de-solder all the links as illustrated in the above sketch, but paying attention to the soldering hints & tips section prefacing these instructions. With all the wires resting outwards from the speaker, unscrew and remove the panel, or panels, which need replacing. Do please remember that if the top panel is amongst those to be replaced, the plastic strip or 'hood' which fits over the top panel must be returned - otherwise you will not be able to re-fit your dust covers! With the new panels in place, proceed to re-solder all the wires and links. When you think you've completed the job with good soldered joints throughout, double-check with the wiring sketch, making sure you've not "missed" the odd link. The omission of only one link will cause considerable distortion.

If you are happy with your work, provide an audio signal and connect the speaker to the mains supply. IF FOR ANY REASON you need to re-check anything, do PLEASE remember to disconnect the speaker from the amplifier and AC mains, after which discharge the HT in the manner described in paragraph 1 headed 'WARNING'.

If the speaker tests out to your satisfaction, reassemble in reverse order of above dismantling instruction (but ignoring the section on removal of the top plate, assuming this has been unnecessary in this operation).

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