philipbarrett said:The coupling caps would be the 27uF films connecting the 6J4 plate to the 1626 grid I assume?
Yes those are the coupling caps, but I hope the value was a typo. 27uf is probably 100 times too big! It could also play havoc with clipping input signals because grid current would want to charge the cap.
Maybe try a smaller cap (much smaller - like less than 0.5uf - I'd shoot for 0.1uf) *and* testing with a smaller signal.
Been through the whole thing with 3 fine tooth combs! Then I got a technician friend (who builds balls-to-the-walls tube guitar amps) to go through it with a 4th! He has all the test gear, dual-trace scopes & the like. Gotta suspect the tubes here at this point.
The up-side of all this is that I've learned a lot. If I'd plugged the thing in & it had worked first time I'd have been thrilled but I wouldn't have got the tube trouble shooting experience. I've had to pore over data sheets, brush up my basic electrical theory, figure out how to test various areas, so it's really been a positive experience.
P
The up-side of all this is that I've learned a lot. If I'd plugged the thing in & it had worked first time I'd have been thrilled but I wouldn't have got the tube trouble shooting experience. I've had to pore over data sheets, brush up my basic electrical theory, figure out how to test various areas, so it's really been a positive experience.
P
MelB said:Philip, have you checked the value of the grid resistor on the 1626's?
good point...grid leak resistors...also what kind of OT iron?
philipbarrett said:Hammond 125 ESE's, all hooked up correctly (believe me I checked)
dang, too bad you don't have a tube tester laying around...what value grid leaks on the output tubes?
noisenyc said:
what value grid leaks on the output tubes?
As Manuel would say, que?
P
274K, BTW, why am I sitting at my computer today? Because Chevrolet cannot design an interior lighting system that actually stays off once you've left the car. Try cranking a 350 with one of those Pep Boys dollar-three-eighty chargers, as my teen daughter would say "sad!"
P
P
philipbarrett said:274K, BTW, why am I sitting at my computer today? Because Chevrolet cannot design an interior lighting system that actually stays off once you've left the car. Try cranking a 350 with one of those Pep Boys dollar-three-eighty chargers, as my teen daughter would say "sad!"
P
hehe count your blessing...now you get to obsess about your non working amp.
and so do i hahah.
274k sounds all good and i'll take your word they are hooked up correctly :0
noisenyc said:
i'll take your word they are hooked up correctly :0
I thought directional resistors were only for the copper-free oxygen cable crowd?
P
philipbarrett said:
I thought directional resistors were only for the copper-free oxygen cable crowd?
P
P your own self. i bet you a pair of .25 old stock paper in oil caps there's a wiring error.
it would be so very rare, a matched tube failure :0
you pay shipping if i lose though.
philipbarrett said:"P" is just my fast signature, since I get about work 100 e-mails a day, short for Philip, y'know.
You're on for the bet tho'
P
heheh p is usually IM for a tongue sticking out.
and yes, i got your caps right here.
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