Quad ESL 63. Adding 1 or 2 more bass panels?

[JarreYuri]

Hi!

I was just sitting here and brainstorming about adding 1 or 2 bass panels to each of my ESL 63.

From what my memory recalls, it will add to the speaker capacitance.
But will the audio transformers cope with it or will it mess up the performance more then I gain in bass?

Any thoughts on this?

Cheers!

[owenhamburg]

So the plan is to mod a Quad ESL 63 and make a Quad ESL 2905.

I must admit I would love you to succeed. I think with 2 extra bass panels, one above and one below the ESL 63 you have the same layout.

I do not know the effects on the transformers, but I would expect that the issues would be minimal, I would be more questioning of the delay line, you could maybe find some old ESL 63 transformers if it does seem to degrade the sound.

My rational is that the transformers in the ESL 63 and the ESL 2905 are both suggested to be driven by amps of a maximum output power of 100W, and you would only be adding an extra two fifths to the total speak capacitance, and think this issue could be minimized by putting some resisters in series with the bass panels driver cable to produce a low pass filter, like the ESL 57 does to make a cross over.

I think the high tension circuity will not be an issue. I think your biggest issue will be the new box to support the new speaker. I think it would be an interesting experiment.

I have never built Electrostatics (Like some on this site), and don't have enough experience or knowledge of ESL theory (Like some on this site) to really comment, but would love you to succeed. I don't expect you will get much lower bass frequencies though, just a little more headroom. I think you will need an active cross over to a Subwoofer to make it movie proof.

Good luck.

[JarreYuri]

Ok!
I was just fantasizing with the idea. And sure, I could do one and compare with the other.
I have 3 units and some extra bass panels too so.... hehe

What I would do is just use new side pillars for the top, bottom and fabric to be supported by and a new longer mounting bracket for the stator units (just an aluminium L-profile).

Yes, a resistor would be in good order to make the extra panels play even lower tones then the other bass panels. Good idea!

[moray james]

as far as I know this has been sucessfully done with no problems. The followin link may be of interest to you. I hope this is of interest, best regards Moray James.

How to Stack ESL-63's by Hey You
check Stewart`s page also, http://user.tninet.se/~vhw129w/mt_au...ir_penketh.htm

here is another valuable Quad link, http://www.quadesl.org/index.html
http://www.quadesl.com/quad_main.html

[405man]

I you read this link there is some more discussion of thios topic

Quad ESL63 / 989

I hope to be able to comment directly soon as I have now built frames to mount the 6 panels and am almost finished with the base section containing the delay lines and electronics, I am off work in a couple of weeks and hope to get a pair built and tested. I shall post more details later

Stuart

[bolserst]

Originally Posted by 405man

I you read this link there is some more discussion of thios topic

Quad ESL63 / 989

I hope to be able to comment directly soon as I have now built frames to mount the 6 panels and am almost finished with the base section containing the delay lines and electronics, I am off work in a couple of weeks and hope to get a pair built and tested. I shall post more details later

Hello 405man,

The link you posted provides good information on the theoretical design work of the ESL63 outlined in the Baxandal chapter on ESLs.
The key point to take away is that for point source dipole ESLs, constant current thru the ESL panels provides a flat response.


Looking at the schematic of the ESL63:
http://www.euronet.nl/users/temagm/a...ematic_new.jpg

You can see that the top and bottom bass panels are driven through R6 & R8 which provide constant current drive.
The current level is determined by the resistor values and was chosen to provide bass output that matches the rest of the ESL63 in level.

If you want to add 2 more bass panels, all you have to do is hook them in parallel with the existing two bass panels.
The current drive level, and therefore the bass output level, will be the same since it is defined by the resistor values.

The difference will be:
1) For the same SPL, the diaphragm in each bass panel will move only half as much as it had been when only 2 bass panels were used.
2) The -3dB down point for the bass will now be lower in frequency.


@ JarreYuri
The added capacitance from the 2 extra bass panels will not cause any problems for the transformer or amplifier. This is because the capacitive load is in series with R6 & R8 so the capacitive load added by the bass panels at high frequency can not make the impedance drop any lower that the value of R6 & R8.

[JarreYuri]

Thanks for the info!

[JarreYuri]

I think I will go for 2 panels.
Then I can just extend the side bars from my 3'd speaker by cutting them and welding them together.

[esl 63]

JarreYuri i have some experience regarding this. It is very possible!
I live in Gothenburg and has refurbished 63s for a decade now :-)
/esl 63