Guitar Research AC60R

[eman]

Thanks for the thread and schematic. I have a friends and the transformer primary is open. So the tranny is not spec'd on the schematic. I do see 7815 and 7915 regulator after which gives me a hint voltage wise and I assume from both looking at it and the fact it is a 60 watt amp that its 6-8 amps current. I'm sure I can't find the exact transformer but something close should do. Any help appreciated. The part number comes up empty A-78-38U. SS 031006 is also stamped on it. This is a 120V version.

Eman

Finding more info on it like that its really just 30 Watts RMS perhaps 2-4 amps @ 12 -24V

Eman

[J M Fahey]

Donīt guess, your answer is on post #28 .

Just read the datasheet and what it suggests, donīt know where you pulled the 12V 6/8A idea from.

One possible problem is that besides the 20+20V main winding, it might also need an extra 12+12V to 16+16V winding, LOW current , to power just the preamp.

I guess that some meant-for-LM3886 generic transformer should be available with the required low voltage winding but if not, use a generic toroid (ANTEK has a few) *plus* a small generic 12+12V 500mA for the preamp.
Being quite small you can fit it almost anywhere.

[eman]

Donīt guess, your answer is on post #28 .

Just read the datasheet and what it suggests, donīt know where you pulled the 12V 6/8A idea from.

One possible problem is that besides the 20+20V main winding, it might also need an extra 12+12V to 16+16V winding, LOW current , to power just the preamp.

I guess that some meant-for-LM3886 generic transformer should be available with the required low voltage winding but if not, use a generic toroid (ANTEK has a few) *plus* a small generic 12+12V 500mA for the preamp.
Being quite small you can fit it almost anywhere.

That guess was before seeing the schematic with the 15V regulators. Thanks for the reply.

ET