Quad ESL63 / 989

[405man]

I am concidering modifying my ESL63s by adding 2 extra 63 bass panels to give a configuration as used in the Quad 989 and was wondering if anyone else had tried this. Does anyone know if the dust cover assembly on the 989 is similar to the 63s

Stuart

[Merijn]

As far as I know from opening mine '63 the complete chassis of te 988 and 989 are different. Allso I have a doubt on the highvoltage supply sinceit is not too overbuild.

Well, I guess you'll just have to try. Stacking a pair of ESL63 on top of each other has been done with a good result. But I do not know how they were wired. I'm actually tempted too...

Be careful with the high voltages involved (5,25 kV)

[SY]

My inclination would be to build some auxillary bass panels, ESL or dipole magnetic, stack them with the '63, and use them at maybe 200 Hz and below. At long wavelengths, you don't really get any benefit from the delay line technology, just more cost and complication.

[sreten]

A more sensible option would be to rebuild the Quads and
add dipole subs/stands , there's plently of info on the net.

http://www.euronet.nl/users/temagm/audio/dipolesub.htm

sreten.

[405man]

I had considered dipole subs but I read that the extra panels allows the point source to be more accurately realised and I have some spare 63 panels from a previous repair. As I work with high power radar the voltages with in the ESL63 do not preasent a problem.

[Merijn]

Oh, and when soldering:

Be oh so carefull with the diaphragm: when using onely 20 W with a very small tip I managed to fry one of the panels without even touching. The diaphragm is very sensitive for heat...

After thinking, the basspanels are integrated in the delayline. This would mean that stacking is possible with only a litthe problem with the basspanels. The supply does only have to maintain the electrostatic field. It works like a conductor, so I guess one could stack them and wire them in parallel with the other two basepannels (no. 8 wire)...

[Merijn]

Found this:

http://www.euronet.nl/users/temagm/a...ematic_new.jpg

[MarcelvdG]

If you want to keep a flat(tish) bass and lower midrange response, you'll definitely have to modify the circuitry at the end of the transmission line, and it is not obvious at all what modifications will be necessary. If you want to try it, the first things to do are to get a copy of the 989 schematic and of

Peter J. Baxandall, “Electrostatic loudspeakers”, chapter 3 of John Borwick (editor), Loudspeaker and headphone handbook, Focal Press, Oxford, 1997, ISBN 0-240-51371-1

This chapter contains a very detailed description of the design of the ESL63 and the reasons why it is designed like that, including things like the resonance frequency and quality factor of the resonance of the bass panels and how the response peak can be removed for by a good choice of the series resistors.

[405man]

Would anyone have a copy of " Peter J. Baxandall, “Electrostatic loudspeakers”" or a copy of the relavent part. I have found someone willing to rebuild my 3 existing panels and supply a 4th..Thanks..Stuart

[MarcelvdG]

405man, could you send me an e-mail?