Quad ESL-63 Info



I've had a pair of Quad ESL-63s for about 6 years now and I've done all sorts of stuff to them including installing new diaphragms and rebuilding them into sturdier frames (made of PVC pipe, of course!).  Here's some miscellaneous photos, drawings, simulations, etc. I've either found elsewhere or done myself.


I used SwitcherCAD III to simulate the function of the delay line in the speaker.  Here are some of the results:


50 Hz

500 Hz

5000 Hz

Frequency Response Amplitude

Frequency Response Phase

The results are quite sensitive to the inductor coupling coefficient, but the value of the shorted inductance has almost no effect on the gross results.  At low frequencies the LC delay line is not very effective.  At higher frequencies it starts to work, but I was expecting longer delays.  Some additional research into the components used in the model is required.

Here is the spice netlist.

More to be added soon...