Quad ESL63 / 989

[Petter]

And they are of course frequency dependent as well ....

Digital is good for such things 🙂

Petter

 

[MarcelvdG]

Actually, the ESL-63 delay line is supposed to be frequency-dependent. That is, the short-circuited windings on the inductors are specifically included to make the line lossy and progressively more lossy at higher frequencies, so that the edges of the loudspeaker get less high-frequency signal than the centre. Apparently that helps to minimise a reflection-like effect which is due to the finite size of the loudspeaker. (If you don't damp the line, the simulated wave front suddenly stops at the edge of the loudspeaker, giving a nasty polar diagram at high frequencies. See the Baxandall story for a good explanation.)

Anyway, I'm sure you could also obtain such behaviour with a DSP, with arbitrary accuracy.

 

[Petter]

The loss could easily be set up but the accuracy will not be arbitrary 🙂

Petter

 

[405man]

This is a nice idea but I do not have the expertise to design a 20-30W amplifier capable of providing +/- 5Kv into a capacitive load and surviving having its output crowbarred by the necessary protection circuit. I would also need 16 of them. I will stick to my original plan to add the 2 extra panels.
Stuart

 

[SkySeeker]

Do you know of anyone building an electrostat using a digital delay?

 

[torroid88]

Adding Bass Panels To the Quad ESL63 ...

As always, for up to date info about Quad, consult Dr Quad first:

http://www.geocities.com/drquad@pacbell.net/

then scroll down to the section "Parts Status" ...

and find "Stewart Penketh of Montreal, Canada" to

see pictures and links. Not that Stewart does add

bass panels, without trying to duplicate the "Point

Source" Ring Electrode Array ...


Good luck !

 

[SkySeeker]

Thanks, that seems to be a mighty informative site.