Donmallonee
The main thing you need to remember is that there are the earlier Acoustats and there are the later, Rockford Spectra Acoustats. Most of what you will encounter out there will be the older Acoustat stuff, with the panels having three wires. The later Spectra series panels have five wires and the transformers/circuits look entirely different. The earlier design is much simpler and easier to deal with, as far as finding individual pieces and as far as doing a repair. The Spectra, not do much. To be fair, I don't have much Spectra experience. At any rate Spectras are complicated. Nothing will interchange between these two different designs.
As far as the 6k capacitors, you won't find high voltage stuff at any current retailer I am aware of. Surplus is the only practical way to go that I know. We have an electronic parts surplus store locally and I have obtained most everything I needed from them. The 3k or 6k stuff isn't always there but, more often than not, I can find what I need. I find individual parts, that is, although no HV power supply capacitors.
You'll have more trouble finding the resistor.
Re-engineering the circuit would take a real engineer with HV experience, for practicality and especially for safety. This 6kv stuff will seriously shock you, if you give it a chance. There is less and less high voltage stuff out there, as we go. I have found several people who are qualified to do this sort of thing but I have found no one who is sufficiently interested to take on such a project. What we really need for Acoustat is someone to do what Kevin Gilmour, and a few others, have done for Stax earspeakers, aka headphones. He/they have very beneficially modified several Stax amps and have designed ground up new amps for Stax headphones. The Stax community has several guys who have published schematics, and made circuit boards, for Stax amps. These are substantial improvements on the original Stax amps. There are people who will build these modified, modern amps for electrostatic headphones. It would be great if some individuals would take on such a project for Acoustats. I simply can't imagine it happening. To a Acoustat guy, this is a sad paragraph.
This probably isn't the place, you asking about Spectras, nevertheless, for a long time, I have been toying with the idea of commissioning a production of the capacitors in the high voltage supply of the Acoustat Servo amps. I haven't checked into doing this for a long time so I don't know the exact state of this sort of thing at present. Those are electrolytic capacitors from the mid 70s. My amps appear to work fine - but - those are 40 year old electrolytic capacitors. If someone out there would join in, and split the cost, and motivate me a bit, I'd get serious about making this happen over the winter.
A properly set-up Acoustat, with appropriate modern sources, particularly a 2+2, or a 6, with Servo amps, remains, at this point in time, about as good as it gets.
Tom
