help with audio resesrch d76

Hifigeek1,
I was wondering if you could answer a question I have, is the arc d-90b triod?
Thanks,
Whitestar23

If you mean the output configuration the answer is no. I believe the output circuit topology is partially cathode coupled, not triode configured.

Thanks Hifigeek,

that is exactly what I wanted to know. You have confirmed my suspicions my tech is a very good solder monkey.

I was talking having my sockets replaced in mine and he said that it was wired in triod. I asked if it was suppose to be he said according to the ARC schematic it was. I asked him to double check and he said he just confirmed it by re looking at schematic in the manual.

This made no sense to me that it could be triod with 80 watts output and that small of output transformers.
They dimensionally look the exact same to me as the Classic 60 outputs.

Well they are different transformers. The CL-60 is triode configured. On the D76, the screen voltage sits at 360Vdc, while the plate voltage sits at 575Vdc. In order for this to be triode configured the screen and plate would have to sit at the same voltage, with the screen and plate tied together through a resistor. Only one voltage winding off the power transformer would be necessary.

HIfigeek,
I meant the transformers from my d-90b look identical, at least external as the cl-60.

Would it not be as simple to run the d-90b in triod as

1. Remove the screen tap leads wires from pin 4 of the output tube sockets
2) Connect a 1 or 1/2 resistor from pin 3 to pin 4 (plate and screen) on each of the four output tubes
3) re bias
thanks and have a good one.