spritzer

There is very little drift in this design so the servo isn't as vital as with the KGSSHV but it helps as the tubes start to age.

Try 1.37K or even 1.2K for the offset resistor. Running without tubes is a very good way to burn up the CCS...

Yup, the gap factoring in the displacement and over all insulation properties of the air.

I like this show a lot, kinda liked the Tunnel too.

Yup, built one in 2012 fully point to point. Sounds much better than the old version plus lower distortion.

It isn't quite that linear and varies from driver design to the next.

Given the issues we had with the resistor brand I'd guess so. Angle brackets are a good idea though. They support the boards and make testing far easier. Easy to drill by hand too.

No schematic but it's just the one off Headwize with the phase splitter now a LTP setup.

All the Stax electrets are pin compatible with the electrostatic models. Similar sensitivity too. Bias is a very relative thing and with transformer boxes you can have low bias but very high drive voltages. Not so much with amps.

Something "new" for people to build. Fully balanced GES Mk2.

The step up ratio of the Sony units was very high, at least 1:100 or even higher. Nothing Stax ever made will work with them. Electret films have a certain charge built in so you design the driver around that instead of the bias voltage. The bias voltage is the same principle, just different implementation. You can't recoat a electret diaphragm to use with an external bias supply.

Gotta love the plate cap not connected to anything.

Electrets cannot be be recharged as they won't ever loose the charge in the first place. Any imbalance has to have an external cause such as broken cable, parasitic charge on the film, damaged driver frame etc. The charge won't "wear out" in the foreseeable future. Never seen electret film for sale and I doubt you could buy just a small roll of it. It's interesting how it is made though, not something you can do at home.

I'm always hoping I'll find some stash of tubes that are worthless to others but perfect for our use.

These are rated to 500VAC and have worked perfectly for me for years. I have one set on the BATE I'm listening to right now.

18.5mm or so for the larger style plug.

He sure did.

The heat sink is rated at 0.45°C/W each so it should work.

The modushop 2U/300mm chassis should work just fine for this but then we need split boards. I also prefer to use angle brackets to hold the boards in place. Makes testing that much easier. Also makes the PSU easier to deal with as there isn't a chance in hell we can make it fit into 300*200mm.

I'll take a stab at cleaning up the board too. I think it would be best to have a left and right version of the board instead of one large one unless we can find a chassis that works for this.

It's been 7+ years since I opened up either of them so I can't remember how you do it. It's a late one so the amplifier will at least work as it should.

I like that build. Nice tube you used too. Are there hoards of these to be found in Japan anywhere?

I know I will build one.

Yes but rated to only 400V compared to the 600V 1486.

I'll check them out. If they are 105°C, with a decent load lifetime and indeed made by Rubycon this could be good.