My DIY electrostatic headphones - Page 8

With a CNC machine you could just make Stax sockets like we did for the DIY SRM-T2 project.  The whole piece is milled from a block of Teflon and the sockets are from the CMC octal tube sockets. 

Really interesting and innovative work! Anxious to hear how your phones compare to a 407. I have a small hoard of the Amphenol 5 pin jacks that are used  in most Stax amplifiers.  As Spritzer says, you can probably make better, but I'd be happy to contribute a few towards your projects. PM me if you're interested.

This is incredible. After you iron out whatever small stuff you want to fine tune and find a build you are happy with======> Have you thought of offering this in a D.I.Y. kit form of unassembled parts/instruction manual for tech minded people to assemble themselves? I am sure you would have a positive response. Having a D.I.Y. set of these would make a person proud.

Truly inspiring.

Dear chinsetawong,

Why not build a headphone that is no longer available but has a unique design like the Stax Sigma:-))

Regards Georg

That arrangement is really food for thought.

I was wondering if you would need to pull out the diaphragms with a very accurate force. If they stay unevenly stretched, you might have distortion.

I was wondering if the PCB (woven glass epoxy?) shield is enough to isolate the outer layer and the inner layer of the second stator.

What happens if you chose to supply inverse bias polarities? You would also invert + and – signal connections in the inner balanced arrange. For instance:

I was wondering the magnitude and direction of all forces and the resultant/net force acting not only in the diaphragms, but also acting in the stators. The second stator seems to be neutral in both arrangements, right?

I was wondering also resonation on the second stator. I do not think the air enclosed between diaphragms cause resonation, but what if you choose to make an imperfect vacuum there? Is there a way to do that? Perhaps it would be a sealed duct within the spacers so you can always reinforce the vacuum and try different air pressures. 

You would avoid air resistance inside the second stator mesh and may compensate occasional differences in the stretch forces applied to the diaphragms during the manufacturing. There would be also an impact in high frequencies interactions between both diaphragms as there would be little air to conduct sound.

But then there would be no air to push forces between both diaphragms, which was you first disign criteria (improve sensitivity).

Do you think this (air pressure between both diaphragms) is some way relevant?

I know sometimes engineering goes in practical models, but I love to simulate or anticipate things...

One last thought now on stator’s temperature.

I was reading those comments on C32 done by a Stax engineer who said they had a concern with the stator temperature so that they made a hole right in the middle of the mesh (stator). According to him that would improve air circulation (I wonder if it also improves the reproduction of certain high frequencies that will not reflect at the thinner mesh; do higher frequencies originate from the middle of the diaphragm or they come from the whole surface? A laser vibrometer would be useful to trace that…)

I think woven glass epoxy boards are less prone to temperature variations than the full metal C32 stators (different specific heat capacities on the materials). And the PCB copper layer is not thick enough to increase temperatures or accumulate so much heat energy.

But given the fact that your second stator will be air isolated, it would be nice to monitor its temperature along certain usage time.

I am looking forward to hearing the results from you. It is a very exciting project.

The heat would really only be an issue with a T2/BHSE pushing (relatively) massive amounts of current onto the stators and even so, only with prolonged periods of that.  Still all metal stators are more sensitive to the ill effects of temperature drift than the PCB based units.