Help needed for Beard P500 valve preamp, anyone own one, or got schematic ??

[David Harris]

Morning all,

Just got a Beard P500 (500 NOT 505 !!) in the workshop for repair.

Does anyone have a schematic, service manual, or just own one ??

The valves, I suspect, are wrong. All four are EF86 (Russian equivs 6Ж32П = 6Zh32P) but the two of them marked in blue are wired for 12vac heaters across pins 4/5 and the other two in red, are wired differently - 12vac one side to pins 4 and 5 shorted and other end wired to pin 9.

As pin 9 on the EF86 is one of the grids, I think the red ones are wrong.

Any clues folks ??

Thanks, David Harris
(aka G8INA, aka Tangram Tables)

 

[gadget73]

The ones with 4 and 5 together and the other to pin 9 is the 6v configuration for a 12a*7 type, but that wouldn' work at 12v. Unless the two are in series?