Pretty much any film cap would work but it's that big as the cheapest caps are often 250V or so and also much more common. This was just lifted wholesale from the KGSSHV board.
No board run coming from us but any of you are free to organize one.
There would be a lot of wires running between the boards but yeah, it would be possible. Also, it isn't 100% clear from the pic but next to the heater connector there is a hole in the board to pass the wires through.
While the tubes will get hot it's above the caps so they won't see too much heat. Electrolytic caps are rated to 85-105°C but film caps can take way more than that.
Here is what I've been doing for the last day or so when time allowed...
This one has the tubes mounted on top of the board to make building and testing far easier. This version uses the old KGSSHV transistors and works with both the fancy teflon tube sockets and the standard ceramic/plastic stuff. This gives the added benefit of extra holes to cool the tubes. Boards are 4.7" x 4.7" and as soon as we are happy I'll order some prototypes.
Marc drew it up (or had it drawn up, can't remember) back in the day and it's basically the front end off the SRM-007t coupled to a CCS loaded quad of 6S4A's. I modified the boards to turn them into a KGST so just one tube per phase and a simple 10M90 ccs. Works well enough but I'll probably put the boards back on a shelf in favor of the ones I'm designing now.
This is a part of larger move to possibly make a limited run of KGST amps. A couple of friends have been asking for a mini Blue Hawaii that would be as slim as is possible for desktop use. The KGST is the most logical circuit for that and it would be fun to do a custom chassis with some over the top PSU design in a separate box. The design is pretty much ready in my head but I simply need to find some time to invest in it and see if any of this can be done locally for me. None of this would be cheap though but that's hardly the point when making something cool...
That's odd behavior but don't mess with the dust covers. Damage them and the drivers are totaled... The most plausible explanation would be the charge leaking to the stators which stops when you force the parts. Could also be a cable issue or the contacts inside the earcups.
Can you get those amps to make some sound? Sure but it will sound like shit for obvious reasons.
A further point that eric is not well in the head, he's running the 009 single ended... Even if the - stator is grounded then the THD is still orders of magnitude higher than when driven push-pull.