spritzer

Having sold all three of my personal KGST's over the last few months I decided to put my foot down and make one I can' be talked into selling. Use a pulled BH transformer that is 230V only (Justin might recognize this one), add a normal bias output and a lovely volume knob by Kevin.

I've thought about it. I could use an extra dac...

Stax were the first to make commercial electrostatic headphones, no doubt about that. There were a few designs that came in the late 60's but most are all but forgotten about now. The old Stax unofficial site was a treasure trove of these but they did also miss a few. The HR-1000 was ok but nothing special.

Never used those.

It wouldn't work in the Dynalo Mk2 but other than that it will work. The new KGSSHV boards have been updated with the MPSA parts in mind.

Most of the Stax sets used A-T drivers so this was never really their "thing".

Yup, that's why it has 500V in brackets next to it.

Stay far away from that AMRG crap imo. They alone are the reason 25% of the SRM-600's have failed while I've never heard of the TKD units failing in any of the other T1/006t amps.

The sinks aren't connected to anything so you can use what ever you like. I do ground them and use the alumina oxide to make it nice and safe.

Only the 600 and 800 had that pile of fail.

Hi there

That's not one of mine. Looks ok though and is probably the Stax "circuit A" from 1968 modified a bit. As for the thermistor, it could be 465ohm so a 470ohm replacement. The higher value makes sense on the secondary but not the primary.

Thanks for that. Better use a smaller pot then and something in series.

What value did you end up with?

Just leave out the last stage. The CCS is changed to a 10M90 (same pinout as the other IXYS part) and use 300 and 1K resistors. The 2SC4686A is changed to the SiC FET

I blame my dad for this madness. He taught me how to solder early on and I had built my first amp at six. It was some battery powered opamp kit but it worked. I then moved to computers but instead of using them for something sensible I ripped them apart and put them together again numerous times. Things went quickly downhill from then on...

His version is the same as mine, I just did the same thing on the PCB level. You know me, I like to tempt fate...

The ESP950 is easy to open, just pull off the pads and remove the 4 screws underneath. Each earpiece simply unplugs from the headband making it even easier.

No good way to do that with our boards. Going this way and using KSA1156 for the front end CCS means only the fets are non isolated. That plus the new batteries will make the amp far easier to deal with.

Some layout changes and the small transistors have been changed to what should be available for the foreseeable future.

They are there to protect the transformers from overload situations so they can be removed. Just don't do anything stupid with the volume...

Not really, I simply haven't run out of the prototype boards yet. It is also far more limited and intended to be run at just +/-400V. Only IXYS CCS and only matched K170 input fets too. There is also the issue of close proximity of the traces so careful soldering is a must have with those boards.

I have to order some more parts in before I can finish this but I have the chassis ready. In other news, new KGSSHV boards showed up today. They've been listed on my website if anybody needs a set.

The one on the left is real but the one on the right... yeah... Even though I have more than 1000 2SC3675's in stock I don't think there is any sense to use them with the 2SC4686A available. Having the main CCS short to the chassis isn't fun...

With the ECR-400 I'd just wire the transformers directly to the input and see what happens. Thermistors don't last for long , let alone 40 years. No transformer I can think of fits the SRA-3S but most of the stock units can be rewired to at least 117V. Some even for 230V...