"Nick Gorham" wrote in message
...
Mike Gilmour wrote:
The labels are just test measurement labels for selecting matched or quad
pairs out of their valve bins. Email the supplier for correct readings
for your amp as it all depends on the resistance value of the output
valves cathode resistors as to what your actually measuring in relation
to the current through the valve.

If the bias is read from that point you can always see what the value of
cathode resistance are and use ohms law to calculate the anode current
from the reading you get on your multimeter at the test points... EL34's
aren't they usually arround 50mA? Its so long since I've used '34's ;-)

Looking at these curves, I would have expected a bit more than 50ma for
HiFi use, maybe 50ma for AB1.

http://www.mclink.it/com/audiomatica/tubes/el34.htm

but as you say, it all depends on the resistor you are measuring the
voltage across.

Keith, what you could try, if you can't get the maker to give the info, is
measure the resistance between the test point and earth, that should give
the resistance you are measuring, so from that you can find what a
particular voltage means in terms of current (do this with the amp off).

--
Nick

Keith, As a matter of interest what DC meter readings do you get from each
of the testpoints with your meter on the mV range? (with no signal input
going through the amp i.e. no music) Its usually the negative meter probe to
the chassis and the positive meter probe to the amp testpoints in turn
noting down each reading to each valve.