My ESL experience

[zhigang324]

Advantages of ESL:
Theoretical distortion is 0, practical distortion is very small yet.
Mebrane of ESL is lighter than Ribbon Laudspeaker, so ESL has excellent transient characteristic.
ESL works on the cool condition.
Shortcomings of ESL:
Moisture sensitive, < 55% of working relative humidity is recommended.
Efficiency is lower.
My diaphragm coating
- Polymer emulsion;
- EC- mechanism of conduction and highly resistive;
- Nontoxic (don't drink it)，no special precautions are required;
- Chemically very stable (withstands UVA/B, ozone, biological degradation, will not discolor upon aging );
- Water soluble;
- Easy for use，1:5 or 1:10 diluting is recommended;
- Perfect bonding to Mylar membrane;
- When it dries，it becomes a polymer layer;
- The layer is tough，conductive，and water-repellent;
- Colorless and almost transparent;
- The added weight of the layer could be ignored;
- Flexible;
- The layer has a long time durability (more than ten years at least);
- Shelf-life of around 12 months;

Stator:
- It is a modular design, some basic modules can be combined into a large one;
- In order to minimize idle distributed capacitances between two stators, stators are designed with PCB, so efficiency and high-frequency response of my ESL are improved remarkably;
- Utilizing design of distributed resonances which has more flat frequency response;
- In order to uniformize driving electro-static force on whole surface of membrane, a design of honeycomb structure copper foil on stators is used.
Membrane material
Mylar, thickness: 3.8μm;
Setup transformer for ESL:
1. Setup is a c-core which is wound from Grain Oriented silicon steel strip and are annealed in high vacuum furnace under protection atmosphere;
2. Multi-sectioned design. Primary winding has 6 sections and secondary winding has 4 (clockwise and anti-clockwise) sections.
3. Excellent frequency and square wave response;
4. Power handling conservatively set at 50 watts continuous;
5. 100:1 turns ratio;
6. Transformers are totally hand wound;

Technical parameters:
Middle ESL:
- Dimension of one unit: 500mm*200mm;
- Spacer: 1.5-2mm thick (Bias Voltage: 2KV/mm);
- Bias Voltage: 3-4 kV (thick of spacer are 1.5-2mm);
- Frequency response: 200Hz – 30 kHz (see figure -);
- Cross Frequency recommended:
For one panel: Fcut>=400Hz;
For four panels: Fcut>=200Hz;
- Input impedance: 4Ω or 8Ω;
- Driving Power (min. / max.): 2 – 80W (R.M.S.);
- Power supply: ~220V；~110V is selectable;
- Working environment: recommended relative humidity is less than 55%.

Tweeter ESL:
- Dimension of one unit: 350mm*70mm;
- Spacer: 0.5-1mm thick (Bias Voltage: 2KV/mm);
- Bias Voltage: 1-2 kV (thick of spacer are 0.5-1mm);
- Frequency response: 1KHz – 30 KHz (see figure -);
- Cross Frequency recommended: Fcut>=1 - 2KHz;
- Input impedance: 4Ω or 8Ω;
- Driving Power (min. / max.)：2 – 20W (R.M.S.);
- Power supply: ~220V；~110V is selectable;
- Working environment: recommended relative humidity is less than 55%.

[chinsettawong]

Hi Zhigang324,

Are you selling these? Picture, please.

Wachara C.

[alexberg]

Looks like advertisment to me... so goes the mass production...
In that case: something made by hand is good in paintings and other arts.
In respect to mass produced amplifiers/transformers/encasing frames etc. everything made my CNC or other machine is usually better due to absence of human errors. Hand wound transformer is good if no other means are on avail. Unless some wierd winding sequence is used machine wound one is better or closer if you'd like to design.
Hand made is expensive if done by qualified staff.
If it's this way not for the artistic/personal expression reasons - there are at least two types of Chineese products: exellent and worthless...

[zhigang324]

Pic. & Frequency Responece of Middel ESL and Frequancy Res. of Tweeter ESL are following:

[a.wayne]

Originally Posted by alexberg

there are at least two types of Chineese products: exellent and worthless...

Zhigang's must be the excellent one huh ? ... More pics Zhigang.................

[thunk303]

Hey Zhigang.

Looking great, cant wait to see the finished units and get a sound report

Can you share with us more about the polymer emulsion for the coating. What do you recommend?

Cheers
Dean

[zhigang324]

alexberg : Looks like advertisment to me...

Sorry, I’m a audiophile and retired electronics engineer, and not a businessman. I build ESL for hobby, not for money.

Pic. of set-up trans. Is following:

[alexberg]

Originally Posted by zhigang324

alexberg : Looks like advertisment to me...

Sorry, I’m a audiophile and retired electronics engineer, and not a businessman. I build ESL for hobby, not for money.

Pic. of set-up trans. Is following:

Sure, that's where hands become handy
Waiting for pics
P.S. CNC for making frame etc. is even more handy

[chinsettawong]

Hi Zhigang324,

It's good to know that you are making your ESL for hobby and not for money. Can you share with us more information on how you build your ESL? You've stated that your stators are made of PCB, do you do sectioning on your stators? Do you put a lot of rivets in order to keep the stators together? Do you mind sharing with us how you make your coating material?

Wachara C.

[zhigang324]

O-core set-up Trans.
1. O-core is wound from one continuous silicon steel strip and there are no joints;
2. The round cross-section improves electric performance of the core. The tight windings and the fact of no shape angles provide a well-distributed magnetic field. The improved coupling reduce magnetic leakage.

Maybe O-core set-up Trans. Is the best one.
But winding O-core set-up trans. is very very difficult by hand.