Originally Posted by i luvmusic 2
Thank You TD!
Sorry been out all day long and wasn't able to make this post for you.
The 12AU7 is run in 6V mode.
Are you sure that those two are IRF 630N's? They are the output mosfets and should be on the other side?
Ok then what are the numbers of the two on the other side?
The LM317 max's out at 1.5A, it provides the current for the mosfets and the 12AU7 filament.
So you can test it by running wires out to a socket matching both sides of the 12AU7 Anode / Gate / Cathode with the 6SN7 pins.
You will use pin 5 and 9 from the bravo socket for your octal filaments, it does not matter which way you hook them up to the octal socket, 5 to 7 and 9 to 8 or vice versa.
The LM317's will probably get a LOT hotter from the doubled current draw, you will have to watch for this and if it gets TOO hot, I'd just forget about the octal in the bravo amp.
Thinking about this further, the two LM317's (to be confirmed by ILM2) are providing 6V to each side of the 12AU7's filaments with the center tap to ground. This also provides a load for the LM317 and for the IRF 630N mosfets. So no you will not be able to run a 6SN7 tube easily. I can't tell you to jumper pin 4 and 5 to 9 with a resistor and use an external power supply on the tube as I do not know what size and wattage resistor you would need to make this work.
You can feel free to experiment, but you do it at your own risk to the amp.
Edited by TrollDragon - 3/9/14 at 5:53pm