DIY Electrostatic headphones and tube energizer

Vaughn

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I've been meaning to post these for awhile but haven't gotten around to it...

All DIY Electrostatic headphones and tube energizer:music:

I'll start with the energizer;

The circuit is taken from here;

http://www.tubecad.com/november99/page8.html

I have owned a few Stax "earspeakers" and associated energizers and wanted to build something that was pure tube (well, except for the rectifiers). I wanted to build the circuit first and get it working before I tweaked anything so no boutique parts were used in the first run. I used good quality parts but no copper foil in oil coupling capacitors; JJ electroyltics, Sprague orange drop, and carbon film resistors in signal path.

electrostaticampunder.jpg


A shot of the underside before installation in the wood (ipe) frame.
Another of the top plate installed in the base...

electrostaticampfront.jpg



With the headphones I had a little help. A friend of mine in Thailand milled the stators and stator spacers on his diy CNC machine from 1mm circuit board material. This proves to be an excellent stator material as it is totally flat, has one conductive side, has a very consistent thickness and is easy to mill. The small tooth at one end of the stator gives a place to solder the cable to.

eslstator.jpg


He also milled the stator housing from a plastic known as Sintra here in the states. Sintra is a vinyl with a slightly foamed core. Here is a picture of the stators, spacers, stator housings and headphone frame. I used a donor headphone frame from an old pair of headphones.

eslheadphoneparts.jpg


Stretching the diaphragm is a little tricky so I made a simple mechanism for tensioning it evenly. The clips grab the edge of the ultra thin mylar (.9 microns). The mylar has to be cut with a hot tool (soldering iron in my case) otherwise it just tears. Cutting it hot creates a very small bead along each edge that reinforces it and keeps it from tearing during the tensioning process. You can see the lead fishing weights underneath that provide the stretching force in each direction.

esltensioner.jpg


While the mylar is tensioned I applied the graphite solution. This is just a mixture of graphite powder, pva glue and water. Once the graphite layer is dry I spray the diaphragm stretcher (also made from 1mm board) with Super 77 and gently lay it on the stretched diaphragm. Working around the perimeter of the stretcher ring I ensure that the mylar is securely attached. Once I am sure I have a good bond I trace around the edge of the stretcher with a soldering iron cutting the assembly away. Here is a picture of the two diaphragms on their stretchers.

esldiaphragms.jpg


A picture of completed headphones. They are a little fugly at the moment but I plan to beautify them a bit. The wrinkled plastic you see is not the diaphragm but a layer on each side that is not tensioned and acts as a vapor barrier (sweat!). I used Koss ESP 950 earpads which worked very well. I also plan on acquiring a Koss ESP 950 extension cable to use instead of the ribbon cable I have presently.

eslheadphones.jpg


So, how do they sound? Damn good:music: The detail one can achieve with electrostatic headphones is nothing short of amazing. I haven't heard anything that allows you to hear into a recording like a good electrostatic (headphone) rig. No room interactions means no room induced colorations. They are definitely unforgiving of crappy sources. My squeezebox sounds like Sh!t with them but a good cd player can be revelatory. I would say these sound a lot like the Stax SR-404, which has a little coloration in the upper mids. Right now I think the energizer is outpacing the headphones, but I have plans to make another pair...
 
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Looks like this project took a lot of big, heavy balls:D...Well, I mean lead weights, right?:yes:

Awesome job from start to finish. :yes:

You do excellent work (not that you need me to tell you)! :thmbsp:

Congrats on the excellent results, too. Being an e-stat spkr owner myself, I can 110% identify with your mercilessly critical, incredibly bad/incredibly sublime yields that are pretty much entirely source dependent.
 
Thanks for the positive comments everyone:yes: I plan on making more of these and I will return here for my affirmation:D Certainly none of my friends or family cares about this stuff:rolleyes:

What did you coat the stators with?

Nice project BTW!!

I'm not sure I understand your question:scratch2: The stators are the fixed panels that are milled from 1mm circuit board material. These are have a copper plating on one side. I think you might mean the diaphragms, which are coated with a solution of PVA glue, water and graphite. I just used the powdered graphite available at hardware stores (commonly used as a lubricant for locks). The graphite makes the diaphragm slightly conductive and allows them to become charged from the bias supply (the Edcor transformer in the lower right of the picture of the underside of the amp).
 
Wow.

What a great project! Thanks for sharing, and for taking great pictures along the way!

I'm duly impressed! :yes:
 
Thanks for this posting. Very informative. I have a few vintage electrostatic heaphones that I hope to play with sometime soon. The energizers are missing in some cases, so I'll be most interested in your progress on the DIY energizer.
 
I'm not ashamed to admit, that after you showing off in the headphone forum, I've been stocking your 'created threads' waiting for this one.

I've been long considering doing up myself a set of electrostatic speakers, but a project of this size seems MUCH easier to manage!

Thanks a million for sharing!!
 
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Wow.

What a great project! Thanks for sharing, and for taking great pictures along the way!

I'm duly impressed! :yes:

Thank you sir, coming from you I consider that quite a compliment:yes:

Thanks for this posting. Very informative. I have a few vintage electrostatic heaphones that I hope to play with sometime soon. The energizers are missing in some cases, so I'll be most interested in your progress on the DIY energizer.

There are a couple of energizers out there I would like to build. I just missed the group buy for the circuit boards for the ExStata amp over on Head-fi. I also wouldn't mind building Kevin Gilmores KGSS amp, which he sells boards for. I have to admit I'm a bit of a point to point fetishist and shun boards in general.

I'm not ashamed to admit, that after you showing off in the headphone forum, I've been stocking your 'created threads' waiting for this one.

I've been long considering doing up myself a set of electrostatic speakers, but a project of this size seems MUCH easier to manage!

Thanks a million for sharing!!

Aw shucks, I'm blushing!:D

So when are you going into fulltime production? That's one heck of a project.

I have done small scale production work for "cottage" businesses and I hate it. I like to build something new each time I build something, which makes it hard to do production!

Excellent! I've been watching the DIY forum waiting for this thread. :)

Here you go! Someday I will really get techno savvy and film everything and post it on YouTube or some similar host.
 
I'm not sure I understand your question:scratch2: The stators are the fixed panels that are milled from 1mm circuit board material. These are have a copper plating on one side. I think you might mean the diaphragms, which are coated with a solution of PVA glue, water and graphite. I just used the powdered graphite available at hardware stores (commonly used as a lubricant for locks). The graphite makes the diaphragm slightly conductive and allows them to become charged from the bias supply (the Edcor transformer in the lower right of the picture of the underside of the amp).

I did mean the stators. I am also an ex-ESL user/owner/repairer and all the stats I have owned have coated stators.

I.e: The QUAD 57s stators are painted in the inside to provide a level of electrical isolation to prevent arcing. The Martin Logans are powder coated for the same reason.

... so I was just wondering...
 
I did mean the stators. I am also an ex-ESL user/owner/repairer and all the stats I have owned have coated stators.

I.e: The QUAD 57s stators are painted in the inside to provide a level of electrical isolation to prevent arcing. The Martin Logans are powder coated for the same reason.

... so I was just wondering...

I see what you mean...

I have some plastic paint I purchased for that purpose but it hasn't been necessary yet. Of course I don't think I'm dealing with the voltages that a large electrostatic speaker is typically using. My stators are at + or - 300 volts.
 
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