"Wally" wrote in message
...
Keith G wrote:

My recent Chinky EL34 amp acquisition comes with fixed bias and
trimpots and no damn instructions. I don't know - is the *bias* fixed
by the valve type, the circuit (which I suspect it does)

A bit of both, as I understand it.

Specs on the web say that the bias resistor (between cathode and ground)
should be around 470R, giving a bias voltage of -28V (at the signal grid).
Put a voltmeter between ground and pin 8 of each octal valve base (valves
in
place), and see if you get something like +28V.


--
Wally
www.artbywally.com
www.wally.myby.co.uk



Fixed bias? with bias adjust pots I would expect the cathode resistor to be
lower at around 10 to 50 ohms. But I stand to be corrected :-)