Wanted: THD BiValve-30 Schematic

[AMPREPAIR]

Hi Folks,
I am working on a THD BiValve-30 head that seems very nice. Unfortunately, no one answers the telephone or emails at THD. Does anyone know where I may obtain a schematic for this amp? Also, is THD out of business?

[AMPREPAIR]

I would like to share the following information:
THD's telephone number no longer works. I also sent an email to THD - but there has been no reply to that either (the address must be valid because it did not "bounce"). I discovered Andy Marshall's telephone number, and again there is no answer - nor does he return telephone calls. This seems very sad as I really like the amplifier I am servicing.