[smart]

I had a lot of progress during the weekend.  The cups are ready for drivers, and one of the two headbands was done.
 

 
A final look of the cups.

 
I use stainless steel wire and a small section of PVC pipe to make the main part of the headband.  
 

 
 
 
Almost done!  The lamb skin is so soft and beautiful.  I still need to do double stitching to finish the band.
 

 

[mungwi]

wow, that looks impressive. good job sir!

 

[livewire]

WOW!
 
Cant wait for the final product impressions.

 

[234537]

That leather band look super comfortable!
 
I am sure you could listen without fatigue for hours!

 

[thelion]

Amazing work that you guys have done! This sounds like a very interesting project.
 
I'm thinking of trying this myself; but I have several questions:
 
1. Will perfectly circular headphone enclosure work, or is an oval better? Stax uses circles, but they have more holes in the mesh they use.
 
2. Several of you are making the mesh out of copper.
 
Suppose I machine aluminum or copper mesh from thick foil with extremely many holes very close together, to extent that the plate is not rigid by itself under stress.
 
To make it very rigid, suppose that at distant but regular points I braze stamped triangles from steel for instance, with thin bars brazed on top of them them (like a bridge truss structure) across the entire surface: it will look like pyramids made of thin trusses. This will cover very few of the holes, as it will be raised from the mesh plate, and if optimized like in a music hall, it will not cause the sound to bounce around too much theoretically.  
 
Has anyone tried this sort of thing? That is, joining a rigid support system to the electrically conducive plates while maximizing the number and closeness of holes on the plate without concern for its individual rigidity under stress?
 
3. Speaking of mylar? Will 2 micron thick mylar that is already metalized work as diaphragm material?
 
Cheers!
 
 
Edit: I also don't have time to make the electrostatic amp itself, and would like to buy one. Which one would work best for home-made electrostats, if anyone knows? I have a usb dac, and mostly have been listening to wooden closed dynamic headphones.
 
I'm mostly interested in making several home-made electro-stats, driver and enclosure, largely because that's what I have tools for making.

 

[n3rdling]

I don't know how small you intend to make the holes, but they shouldn't be smaller than the stator thickness. 
 
Metalized mylar will work, but the resistance is much, much higher than what most recommend ( ~ 10^6 - 10^9 Ohm/in IIRC).  Current will be higher on the diaphragm and thus metalized Mylar is more prone to flammable arcing than other common solutions.

 

[n3rdling]

Awesome thread btw.

I've been putting off reading this thread until I had more free time - about halfway through, gonna read the rest tonight.

 

[spritzer]

Metalized mylar is too conductive to work on a constant charge basis.  You can get it to work but distortion will be higher. 

 

[chinsettawong]

Hi thelion,
 
You probably haven't read through the whole thread.  
 
1.  Yes, the circular shape sounds very nice too.  Actually you can make them in any shape you like.  The most important thing is that they should have sufficient diaphragm area so that they can play full range.  With small diaphragm area, your headphones won't have good bass. 
 
2.  I always make my stators using copper clad PCBs. They are good and cheap.  I'm sure your method works too.  If you like to try it, just do it, and let us know how it goes.
 
3.  You can try.  There is a guy that I know making his ESL with metalized diaphragm and he says it sounds very nice.  However, he puts very high series resisters into his bias circuit (a few hundred million ohms).
 
Wachara C.

 

[chinsettawong]

My New Orpheus is officially done. Thanks to the headband and ear pads from Smart, not only that they sing wonderfully but they are also so comfortable to wear.  This is so far the best pair of headphones that I've made. 

 

 
As expected, the sound stage is big and the bass impact and efficiency is just right.
 
I have a pair of SR007 MK2 with me to compare.  My New Orpheus sounds much brighter in comparison.  The sound stage is wider and the sound is a little louder at the same volume level.  I think that they must come from the larger diaphragm area.  However, SR007 MK2 still has just a little better bass. 
 
Wachara C.

 

[spritzer]

The HE90 is pretty bright and weak in the bass so you might just have nailed it then. 

  What did you for the cable on these?  I like it, very retro Stax. 

 

[chinsettawong]

Quote:

The HE90 is pretty bright and weak in the bass so you might just have nailed it then. 

  What did you for the cable on these?  I like it, very retro Stax. 

 
Thanks, Birgir!
I use Koss 950 extension cord.  It's cheap and good. 

 
I'm sure you like my ear pads too.  They are made thicker at the back just like Stax Omega's. 

 
It's too bad that I don't have HE-90 to compare right now.  Will report on that when I have a chance to compare.
 
Wachara C.

 

[spritzer]

Angled earpads are a must have. 

  I must say I attributed the diffused imaging of the HE90 to the flat earpads for all this time but our FrankenSennStax shows it's mostly due to the drivers as these image just fine. 

 

[ForzaPC]

Dammit man, you make me want to build my own CNC mill!
 
Great build!

 

[peterroumian]

me too
 
wachara, i had an idea for improving the design of the holes. here it is - tell me what do you think. Left is the "original", right i think might improve air flow. it's important that the copper is untouched because if we go deeper it may start to peal