I spent several weeks working on the speakers. I worked deliberately slowly as it was exciting and fun. The gluing operations cured extra long time to be ensure correct results. I removed and replaced seven diaphragms, re-glued two stators completely and enhanced the glue between stator and matrix on all remaining panels.
Clips were added to the long sides of the black panels. Both high voltage boards needed attention. Both voltage regulator circuits had a too high output voltage. I ran into some problems during the repair. I corresponded with Rob using email and always got solid and good advice how to solve or overcome my problems. So finally the repair was done.
The speakers were powered up and ready to play. No clicks, pops or hiss were present. The sound was very clear and detailed, maybe a bit harsh. The bass was surprisingly solid and deep. Over the days the sound has now matured and the treble is still very clear and detailed and now also completely smooth without any harshness.
Only plastic film supplied by Acoustical should be used. Specify whether for bass or treble unit when ordering. First remove the faulty unit from speaker as described on page 4, and strip the adhesive tape from around its edges to release the two dust cover frames. On bass units carefully disconnect the three wires from the terminal board, having noted their positions, and remove the board. Clean all loose dust cover material from the wooden frames since any pieces left to flap will buzz.
Spread enough of the new dust cover material on to any clean, solid, flat surface to leave about 6" surplus all around the frame, and hold in position with pieces of adhesive tape at each corner and at intervals along the sides as required.
The materials should not be over stretched but just tightly enough to remove the wrinkles. Adhesive can now be applied to the frame, the frame placed into position on the material and left to dry. The adhesive should preferably be of a type which does not set brittle, such as Samual Jones' Samson C, Evostick, etc.
When this is dry, use a razor blade to trim off all surplus cover material back to the edge of the frame. If pierced cold the material will in time split and run the whole length of the dust cover. When a pair of covers have been made, the unit and the covers should be blown with a jet of dry air to remove any dust particles etc. GREAT care should be taken if it is found necessary to renew any soldered joints on the plates.
Anything more than a quick touch to the tags will soften the plate material and loosen the solder tag. A heat sink is helpful here. When reconnecting to the terminals be sure not to cross wires as this will result in the failure of the speaker to work.
This completes the recovering and the unit can now be reassembled into position in the speaker. At serial number March additional filtering was added to protect the treble unit from damage due to high level low frequency signals. Earlier speakers may be modified as described below, when they are to be used with the Quad or other suitable amplifiers of comparable output.
The components required can be obtained ready assembled on a tag board, if required, and Fig. Alternatively, suitable resistors and capacitors from normal servicing stocks, may be used if preferred.
The above figure shows the tag board layout from serial number onwards. Modifications to loudspeakers earlier than serial number when used with the Quad amplifier.
Service Manual Details Hits: All material below is from an old Quad service manual, and is not intended to be highly informational to the novice refurbisher.
Distortion Make sure that the speaker is really at fault by comparison with a second electrostatic speaker, using a Quad amplifier. Check EHT voltage Suspect intermittent breakdown in speaker units. Suspect intermittent breakdown in audio transformer unit. Note: a fault in this unit is very unlikely. No Output at All Suspect EHT unit or audio transformer unit after checking more obvious things like external connections, not forgetting the leads under the transformer unit connecting the input sockets.
Background Noise One cause of background noise in the electrostatic loudspeaker is internal discharge of the EHT supply at times of high humidity, or high voltage, or both. Replacing the Front Grille Replacement grilles are normally supplied cut and pre-formed so the procedure is as for refitting an existing grille. Find Posts New Posts. Install the app. JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding. You are using an out of date browser.
It may not display this or other websites correctly. You should upgrade or use an alternative browser. Thread starter Thinker Start date pm. Thinker Member. The problem one is currently having is that it's playing back at reduced volume, no pops, hiss, crackles, or distortion, just reduced volume. I would like to rebuild it with slightly beefier components and I was wondering if I could get some suggestions from those who are more familiar with the 63's.
I know you can buy pre-done boards but, where's the fun in that? Voltage 3. A Reverse Current 2. Current 5. And should I change any of the resistors on the EHT board? More options. Manolo47 Member. Are you sure it's that? It could be one of the panels. Pretty sure it's reduced HV, especially with the neon bulb acting that way and no sparks, crackles, hiss, zaps when idling or distortion when playing.
There's three things that I've seen go bad: The MOV in the front end, the diodes, and the capacitors. Typically the diodes are my first suspect, and I shotgun all the diodes.
I then check the MOV. The voltage going to the multiplier string should be about V. IF that's correct, and the diodes are replaced, I then shotgun all the ceramic caps. The neon bulb should flash when the speaker if first turned on and then blink slower and slower as the panels charge. If you are in a dry climate and have good clean panels, it can be 30 seconds or longer between flashes.
Because you have low output, that board is a reasonable place to check. One easy thing to do is to swap bases between speakers and see if the problem follows the bass or not. The bases are held to the panel assembly with 8 nuts and three wires plus antenna.
0コメント