Old Kay amp needs attention
This is a very old guitar amp probably from the late 1940's. I believe it is single ended in that it has an 80 rectifier tube, a 6C5, a 6N7 and a 6L6. The socket for the 6L6 says 6N6. The amp works but I can see on my variac amp meter the current draw goes down instead of up when I strum the guitar. This seems odd to me as all other amps I've tested this way increase the current draw. It also seems to have a large current draw at idle, (no input signal) at .9 amps. The amp has had some work done, perhaps a lot as much of the circuit has been rewired and new capacitors. What if anything is out of the norm here? In other words shouldn't the amp meter rise with a strong input signal? If so what might be the reason it's decreasing?
Cette question est-elle utile ?
@bigdrums I'd start by replacing the 6N6 with a 6L6 or a proper substitute for that.
That was already done when I got it. I am thinking that whoever rewired it got the plate, the control grid, and the screen grid wires mixed up. Without the 6L6 in place I measure 472v on the plate, pin 3, 474v on the control grid, pin 5, and 476v on pin 6 which is supposed to be unused. From my notes on previous projects using 6L6's pin 6 sometimes has the highest voltage for what I don't understand. then the plate then the screen in descending order.
par Jim Mcsharry