One Thing Audio
Quad
Instructions, New dustcovers for ESL 63

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Warningdown

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.

Instructions top

  1. Before starting: two layers of what is sometimes called 'duck' tape (black cotton-reinforced tape) is used on the standard ESL 63 - one layer around the top of the speaker, the other around the bottom - to hold the metal grilles tight to the frame and to dampen vibrations. If the old tape is carefully peeled off, it is usually possible to re-use it. Some people use 25 mm PVC tape, which will suffice, but the closest (and cheapest) equivalent to the tape used by Quad can be obtained from Farnell www.farnellinone.co.uk), or tel. 08701 200 200. Part code number 19-0433.

  2. To remove the ESL 63's wooden top: press down and slide firmly to the RIGHT. If this doesn't release it, tap sharply from the left: (rubber mallet is ideal - try to avoid damaging the veneer). This should release the top from its fixtures.

  3. Pull the top 'wrap-over' section of the stocking off it's Velcro fixture. Roll the stocking down the speaker, low enough so that the bottom layer of duck tape is visible. Remove both layers (top and bottom of speaker) of this tape. Save for replacement, or refer paragraph 1.

  4. Using a flat screwdriver, prise outwards the top comer of the grille from its 'rail'. Insert forefingers behind the gap and slide downwards. This will release one side of the grill entirely out of its rail. Gently ease the opposite side of the grille out of its rail. Do the same for the rear grille (assuming you want to replace the rear dustcover as well). Note: 'duck' tape is also used down each edge of the grille. If the glue has dried out, the tape will want to part from the grille. Allow it to do this, retrieve the tape and re-glue it back onto the grille (or use new tape, see (1))

  5. With the same flat screwdriver, ease out one comer of the dust cover frame. Insert forefingers behind the gap and slide downwards. Do the same for the other side of the dust cover frame. Ease the bottom and top central sections away from their respective tracks. Slide out the frame to the left, or right. Repeat for rear dust cover if required.

  6. Removing the old or damaged dust cover from its frame is an easy matter. Do NOT attempt to remove the original double-sided tape from the frame: this has remarkable adhesion and will not easily be removed. Instead, bum out the original dust cover with a soldering iron, moving the tip of the iron inside the frame, all the way round, making a 'clean cut' of the original damaged dust cover.

  7. To affix new dust cover: clean the surface of the frame with isopropyl or acetone (or if neither is available, just make sure the surface is free of grease or dust). Onto this frame, over the old tape and remnants of the old dust cover, re-glue four strips of the double-sided tape provided. At this point, do not remove the protective film from the front of the tape.

  8. You need a clear, flat surface for the next operation (table-top etc). Using the frame as a template, cut out a square of the dust cover film big enough to overlap the frame (say, by 12" or 30 cm all round). Put the frame to one side for a moment. This square of film must now be tensioned so that it lies flat with no creases. Use short pieces of sellotape to achieve this - starting off with one on each corner of the square of film. Do NOT pull too hard - the film is very delicate and only slight pressure is needed. Then use another bit of sellotape half way down the long run, then half way down the short run. If the film is now uniformly flat and free of creases, leave it at that. If not, add more sellotape until you are satisfied that the tension is reasonably even and no creases remain.

  9. Peel off the protective film on all 4 runs of the double-sided tape. Be careful here when handling the frame now that the very sticky surface is exposed. Now lower the glued surface of the frame gently down onto the square of dust cover film. Run finger pressure all the way round to ensure the glue has stuck properly. Peel off all the bits of sellotape and lift up the frame. Run a hot soldering iron round the periphery of the frame to bum off the dust cover overlap.

  10. ALTERNATIVE WAY OF ATTACHING THE FILM: this perhaps takes a little more skill, but is quicker. 2 pairs of hands are needed - so conscript a helper. Place the frame (as prepared above) on the flat surface. Peel off the protective film, so that the sticky surface is uppermost. With 4 hands, pick up the square of dust cover material- DON'T tug at it. It will tear easily. The film is quite strong if handled gently. Hold the square of dust cover film over the frame and pull GENTLY on all four comers until it is taut and reasonably free of creases. Then one pair of hands (nominate who!) should lower their side down - but don't let go! Hold the film down whilst the other pair of hands lowers his/her side down - this way it is still possible to make tiny tension adjustments to get the film to lie as flat as possible.
    Don't worry if there's a few small creases still present: it is too late to do anything about it now, and they should disappear when the cover is subjected to heat-shrinking. NOTE: if you've made a mess of things, don't worry: there is plenty of film supplied for you to have several goes, if needs be. Unlike the original layer of sticky tape, the new tape (before it has had time to cure) is reasonably easy to 'roll' of with thumb pressure, so you could, if necessary, start from scratch again.

  11. Clip your completed dustcover back onto the speaker's frame. Start by engaging one corner on both the vertical and horizontal 'rail' (if you don't engage it on both, you'll have to ease it off and try again). Once the corner is engaged on BOTH rails, with firm thumb pressure move along - it should now clip on easily all the way round.

  12. TENSIONING: Hair dryers seldom get hot enough to heat-shrink the dust cover, so a cheap heat gun will be necessary for this final task. (A decorator's hot-air gun will also do the job, but ensure that it is used on its lowest temperature setting). IMPORTANT NOTE:  If the stocking is bunched up around the base of the speaker, place a damp cloth over it to protect it from the heat gun. With the gun's nozzle about 12" (30 cm) away from the dust cover, move from side to side. Always keep the gun on the move. NEVER dwell on one spot, as this will bum a hole in the film. If the gun is kept moving from side to side, or up and down, all the wrinkles will eventually disappear.

    Replace grilles - re-glueing the tape to the vertical edges if it has parted from the grille, or renewing the tape if necessary. Finally, renew the 'duck' tape around the top and bottom of the loudspeaker - twice round the speaker should be sufficient.
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