The Single Power ES-1/2 repair and restoration thread - Page 8

It's indeed no BHSE but it should be more then comparable with the Woo WES (if a bit different) and show the other "high end" amps just how inferior they really are. In the end one must pick what kind of sound you are after, the BHSE/T2 offer us stark reality though it is never forced like with so many "neutral" components. What you have is just a very linear amp with enough power to swing voltage into any impedance presented by the transducers. With the ES-X (and the Woo WES) you are dealing with the limitations of vintage tube design. A plate resistor will never be as effective as a constant current source in dealing with the wild impedance swings of the transducers but the amps make up for it by being able to swing a lot of volts, far above what we truly need.

As for the Stax amps, they are built on a shoestring budget and all of them are DC coupled so there is a difference in presentation. The 007t is an easy target but the 717 would be tougher to beat if not just for the fact that is is less than 1/6th the size of the ES-1. That said this is after all a Stax amp on steroids so a similar take on the SRM-007t might sound pretty nice...

You could put in something like Kerry's Blue Hawaii PSU and move on to AC filaments. That takes care of the PSU but the amp section is harder to fix. You could keep the PCB but it requires a bit of modding to get it right but given the huge size of the chassis, you might just as well rebuild the amp, point-to-point. Personally I'd scrap all the parts on the amp PCB, sell the AN silver caps and just start from the beginning. It's not as bad as it sounds, about 300$ for very good parts. I'd also replace the 4 50W resistors (the golden ones) with the ones I used which are Mills non inductive.

That is indeed the problem but have you talked to Wayne from Bolder Cables? The schematics are all available and it shouldn't be too hard for him to turn the amp back into something useful.

Even if the amps work they will chew up tubes so at least sorting out the filament supply is a good idea. A real bias supply is also a good idea (the stock amps are far off spec) and adding the C- supply plus the extra adjustment to the first stage is well worth it and quite cheap in terms of parts used.

I updated the third post of this thread today with the final installment of this saga.

Wise choice indeed. It does sound pretty good now with an all tube signal path (ECC99 with transformer output in my APL3910) but stock it was very much a let down.