[ts8051]

The other pieces such headband and cases are made with my 3D printer and PLA plastic.

 

[ts8051]

I cannot post yet photos.

 

[chinsettawong]

Actually it's better that you save your photos somewhere else and post your links as images here. That's how I do mine.

 

[ts8051]

  

 

[Muamp]

That's a cool looking headband and surround! Some construction notes would be good.
And still a picture of your stretcher frame would be appreciated.
 
David.
 
Edited: Is the active area really 12.5cm? Or is it 12.5cm overall surround dia.

 

[ts8051]

The diameter of membrane only are is 12.5 cm

 

[chinsettawong]

That is huge! And you are using that with the spacer thickness of only 0.4 mm. It's really incredible that you still can get good bass. Is Mylar the material you use for the diaphragm?

 

[ts8051]

yes it mylar 2micron from taiwan.

 

[chinsettawong]

Hi ts8051,
 
I really don't know how you do it.  From the picture, you'r using single sided PCB for the stators.  You said earlier that your stator thickness is only 0.6 mm.  Do you use PCB that has a very thick layer of copper?  
 
For all my headphones, the maximum diameter of the active area is only 80 mm.  And yet, it's not so easy to tension the diaphragm on the 0.5 mm spacer so that it's stable and produce good bass.  
 
I only can guess that you are driving your headphones using a pair of step up transformers and the bias voltage is quite low too, right?
 
Please tell us.  How do you drive your headphones?  What is your bias voltage?
 
Wachara C.

 

[ts8051]

The bias voltage is 580v as i use stax ergizer. the copper layer on stators is thick 80micron. After mylar tension and apply conductive material, I attach the spacer psb's on it with epoxy glue. Also I clean  with aceton the excess of glue in order to have a clean membrane attached to the spacer pcb. After 24 hours with a small soldering iron I remove the glued pcb's. Please note that in this stage because of high tension and low thickness of pcb's we observe a distortion. When I put these with other pcb's (stators and the other spacer with copper) the whole system is flat. The secret for success is tension and the quality of glue.
This is not the only ESL headphone is was constructed. Before this I constructed with the same method a rectangular in shape headphone with success.
Please note that I studing with experiments the ESL Construction from 1985 with i was a student in Physics and studied the N. Pollock article from wireless world magazine. 

 

[Muamp]

Hi ts8051,

Could you please tell us where you purchase your FR4 @ 0.6mm with 80 micron copper. The thin fibreglass with such thick copper sounds like a good choice.

David.

 

[chinsettawong]

I guess the spacer together with glue should make your total thickness of at least 0.6 mm already.

Have you compared your headphones loudness with other Stax headphones to see how much louder or softer your headphones are?

 

[ts8051]

Hello,
My headphones are louder that my stax sr407, but sr407 is more musical.Now i am looking for the reasons caused it and then i will develop new designAlso i observed that my headphones are ply better with transistor based energizer rhan with my stax tube energizer. I suppose that this happens because of vey high capacity berween plates.
My other designed headphone rectungular in spape with total 20% lower active membrane surface plays better with my tube energizer. Possibly the stax tube energizer cannot accept very high capacity.

 

[ts8051]

Hi ts8051,

Could you please tell us where you purchase your FR4 @ 0.6mm with 80 micron copper. The thin fibreglass with such thick copper sounds like a good choice.

David.

In Athens, Greece i ordered the pcbs based on my Design.

 

[ts8051]

 
 
My previous rectangular in shape ESL Headphone.
Active membrane dimensions: 76.2mm X 96.52cm)
Stator 0.6mm
Spacer 0.4mm