EL84L amp fixed bias.....

[tubedogsmith]

Long time gone and this one is sorta off the reservation. El84L power section with fixed bias. A long time friend approached me with this idea a while ago and I wasn't nuts about the idea but finally came along. Glad I did. Super cool amp, crazy smooth and you get such contact and feel from the amp when you dig in it's nuts. Out of all these I've built this is the first one that really has the output section just kinda take over the response and overall experience. Anyway, old dog, new trick....

[Colossal]

Super nice build!

What is your plate and bias voltage/current if you don't mind my asking?

[tubedogsmith]

Plate voltage is 390v and I have them biased to 9.5 watts per tube.

[10thTx]

Is there a chance that you'd have a schematic that you'd be willing to share, please? I'd be very interested in seeing how you approached this and some of the values of caps/resistors using EL84's?

With respect, 10thtx

[tubedogsmith]

I haven't written this up. The main amp is pretty much a low plate skyline circuit with a 250k OD trim on the board and a 250K drive pot on the front. There's a loop a lator built into it with the power coming of the screen cap. The bias circuit is similar to the old 50 watt plexi model. Tap on one side of the PT hot secondary with a 150k resistor to the diode, a 47k resistor, 2 47uf caps, 10k pot with 9k resistor to ground. I messed around with this for a while and ended up with -14.5v on the tube grids. Spent more time getting the bias voltage where it needed to be than anything else.