Now that you point out how the circuit is wired, it totally makes sense that I can’t get a proper reading of that resistor value while it it soldered in place – thanks for pointing that out. I was going along measuring resistors on the eyelet board, and they were all measuring at the expected values except for that one – but now I clearly see why the measurement wouldn’t work for that one. I’m learning quite a bit from this process – thanks!
Robin – I’ve had inconsistent results with poking at various components to see if the noise changes/goes away. Most recently, it seems like poking at the eyelet board doesn’t do anything about the noise. A few days ago, it seemed like poking at *anything* on the board would stop the noise.
As far as the speaker question, here is what I’ve tried:
– 8″ speaker alone
– 10″ speaker alone
– both speakers together
– amp plugged in to external 1×12″ 16 ohm egnater cabinet with impedance switch on amp set to 8 ohms.
The static noise is the same in all cases.
Two additional observations:
1. Turning down the tone pot makes the noise much reduced – but I think that this is only because the noise is in the high frequencies, so it is “rolled off” when the tone control is turned down. I disconnected to the tone control from the volume pot, and the noise is still there.
2. The noise is not there when the amp is just turned on from a “cold” state. It becomes audible after about 3 – 5 minutes. If the amp is briefly powered off to switch tubes, the noise is there immediately with the new tube, so it doesn’t seem to be a function of the tube warming up, but some other part of the amp.