DIY ESL Pannel Parts Shopping in EU.

[owenhamburg]

Dear all Europeans,

I propose we have a thread on where to get parts for building DIY ESL panels.

It seems we need 4 main things

(a) Mylar
(b) Stators
(c) Transformers
(d) HV supply
(e) Mylar treatment
(f) Other bits

For (a) I am still looking for a cheap solution.

So for (b) I can get perforated aluminium sheet at the local DIY store MAX BAHR - Schön, dass Sie da sind. but I doubt you can see it on line.

For (c) I am still looking for a cheap solution.

(d) does not look hard at all, just a lot of high voltage diodes and capacitors, maybe bees wax is also needed?

(e) It took me a great deal of time to source "Techspray 1756-8S Licron Crystal Permanent Static Dissipative Spray" in Europe but I found it, here somersetsolders from the uk. Shipping is a bit high, for me in Germany, maybe others have found cheaper suppliers in Europe? It might be the stuff the USA people have been talking about in this forum.

(f) I am still looking for a cheap solution for spacers and holding insulators, locking the mylar and the frame. Nylon is too conductive for HV? I saw something about using plastic window frames.

I would like this thread to focus on finding parts for ESL's as I fear it would get lost is the parts section I post it in the ESL section. I favour the idea of making some headphones as I love my ESL 63's and headphones are better for late nights. I'm using PCB material or the sheet aluminium from MaxBahr but I hope this thread can avoid being limited to my plans just places to get parts for electrostatic panels.

Regards

Owen

 

[CharlieM]

Hi Owen,
The hardest items to find here in the US are suitable step up transformers. But that shouldn't be a problem on your side of the pond-- a pair of inexpensive 50VA 230V/6V toroids (two per speaker) will give excellent performance in a hybrid speaker and they're readily available in Europe. I highly recommend the Licron Crystal diaphragm coating too.
Good luck with your project!
Charlie

 

[SEdwards]

Have you seen the DIY electrostatics headphones over at HeadFi? There are several guys building at the moment.

Cool that those toroids would be enough, I'm curious too now.

 

[CharlieM]

Cool that those toroids would be enough, I'm curious too now.

Here's a simple, cheap HV bias supply and tandem 2x115v/2x6v transformer setup for a hybrid ESL (about 75:1 step up ratio). I prefer the single primary 230v/2x6v transformers which are easy to find in Europe but are not sold in the US. A single pair per speaker would not suffice for a full range ESL but they're perfect for a hybrid panel crossed over at 200Hz or above (conventional woofer supplying the bass). The schematic and a parts list are on my ESL web page (link below).

 

[owenhamburg]

Hello Charlie,

Thanks for the advice on 50VA 230V/6V toroids (two per speaker). These are easy to in Europe as our voltages are sort of standardized to 220 - 240 V converging on 230V. Do you have any suggestions on how I can judge one from another?

I found this one : Triad Magnetics VPT12-4170 but it is a twin primary model.

So maybe MULTICOMP - MCTA050/06 model is better?

Regards

Owen

 

[owenhamburg]

Have you seen the DIY electrostatics headphones over at HeadFi? There are several guys building at the moment.

Cool that those toroids would be enough, I'm curious too now.

I have seen one of them, probably the first, but am more interested in this thread to focus on parts available in Europe. If we get a full house I may well start building my project

Regards

Owen

 

[CharlieM]

Hello Charlie,

Thanks for the advice on 50VA 230V/6V toroids (two per speaker). These are easy to in Europe as our voltages are sort of standardized to 220 - 240 V converging on 230V. Do you have any suggestions on how I can judge one from another?

I found this one : Triad Magnetics VPT12-4170 but it is a twin primary model.

So maybe MULTICOMP - MCTA050/06 model is better?

Regards

Owen

Both of those transformers use dual 115v primaries, which will indeed work but I believe a single primary transformer would be more robust, less prone to arcing. I would use the one shown below, from the same supplier:
VTX-146-050-106 - MULTICOMP - TRANSFORMER, 50VA, 2 X 6V | Farnell United Kingdom

You want to use two of those transformers per speaker, with the (4) 6v windings wired in parallel on the amp side with a 1-Ohm/10W wire-wound resistor in the positive lead, and the 230v windings on the output side wired in series with the negative lead from the HV bias supply tapping in between the two 230v windings (as shown in one of the schematics on my blog page).

As I said earlier, this setup is not suitable for a full range ESL... you will need to use conventional woofers for the bass. And, unless you know how to build a passive crossover that can accommodate an electrostat's wildly varying impedance (I don't), you will need to bi-amp the speakers using an active crossover in front of two amplifiers--- which will sound fantastic and a hell of a lot better than any passive crossover/single amp setup anyone could ever build.

 

[Bazukaz]

Hi,

I am using 80VA 230:11.5V toroids from a Poland firm called Indel. These look tightly wound and measure quite well : harmonic distortion < 0.05% within a range of interest; internal resonance above 20 kHz.
I use 6 of them per speaker yielding a measured turns ratio of about 1:115. Can handle about 12Vrms@50 Hz so no problems using with a sub crossed at ~80Hz with a 60W@8Ohm amp. Somewhat of a problem is relatively high internal capacitance but its expected with most of mains toroids.
Do not know if these are available in your country.

Regards,
Lukas.

 

[owenhamburg]

A mylar / Hostaphan polyester film source

Dear Lukas and Charlie,

These cheap transformer solutions are very interesting. What impedance does the power amp see for the speakers / transformer?

Also I found this site that seems to sell the Mylar, or I guess more appropriately polyester.

10 m roll of 3 µm Hostaphan® polyester film (65 cm wide) - 25 Euro plus S/H

I also found a source in China selling via ebay (uk) but I would rather source all in Europe. Neither are much cheaper than the other, and I am sure the prices could be a lot lower but since I am not likely to need all 10 m, I think, and am not planning mass production, I can live with the price

Regards

Owen

 

[Bazukaz]

Hi,

The transformer array I am using gives a very roughly approximate load like a 5-7uF capacitor(varies with freq.) at amplifier terminals up to trafo's resonance at 21-22 kHz. After that impedance would increase. I have measured with a segmented wire ESL connected. The panel has relatively low capacitance@20 kHz due to small treble segment size of 2x150 cm. So most of the load is from transformer's parasitic capacitance. But if you don't plan to go for full range with mains toroids and 6 are not needed it's very likely capacitance will be a lot lower.
I am torturing an LM3886 amp with this and it seems to not care very much about the heavy load.
Also its very important the amplifier has as low DC offset as possible when driving toroid trafos. IMO should be no more than a few mV unless series resistor or capacitor is used.

I have bought Mylar from e-bay china sources(2u and 6u). It looks like Mylar from china is stronger and more stable than Hostaphan(it's my personal opinion only, so take it with a grain of salt). It could really be Mylar grade C after all.

Regards,
Lukas.

 

[Nossaile]

Full Range Transformer

...As I said earlier, this setup is not suitable for a full range ESL...

Any experience on what transformers we needed for a full range ESL and why?

 

[Bazukaz]

Any experience on what transformers we needed for a full range ESL and why?

Read my post #8 in this thread.
For full range ESLs you need mains toroids that have higher voltage on the outer winding to prevent core saturation in low frequencies.
1) For A semi-full range crossed to a subwoofer in 70-100Hz 12:230V transformers should be enough assuming active crossover is used. That's if you don't plan to use amplifier more powerful that about 80W/8Ohm.At least 4 or better 6 will be needed to obtain a reasonable total turns ratio.
2) For a complete full range no less than 20:230V transformers may be required and one would end up having to use 8 of them just to get turns ratio close to 1:90. IMO that would be more expensive than buying specialized trannies.

 

[john65b]

Bazukas, You are using a LM3886 on ESL panels? That poor amp! What rails are you at? How's it sound?

I have always wanted to try them (I have a few LM3886 and LM4780 modules just sitting around)

 

[Bazukaz]

Bazukas, You are using a LM3886 on ESL panels? That poor amp! What rails are you at? How's it sound?

I have always wanted to try them (I have a few LM3886 and LM4780 modules just sitting around)

To me it sounds good. I would not consider it a poor amp. Low distortion and robust. Has a current limiting of around 11.5A according to datasheet which is not bad either. However quite sensitive to PCB layout.
I am running it at +/-34V.