The good thing is, the amp works…it’s got the correct voltages in the correct spots. The problem is some of the signal isn’t making it through somehow to the output. If I understand you correctly, every time you re-flow/re-solder some stuff on the board the amp gets louder. To me, that’s a sign that there’s some sort of connection issue…most likely it’s something that’s not making a good connection somewhere (as opposed to a short)….only letting a bit of the signal through. If you are at all un-confident about the solder joints then please check them again…look very closely at each joint. I know it’s a pain, but that seems to be what all signs are pointing toward.
Just checking, you are using an 8 ohm speaker, correct?
If all the tube voltages are correct then the tube is working correctly. Besides that, we test every tube before we send it out, so there’s very little chance that it’s a tube problem. Vacuum tubes contain a bunch of tiny parts, very close together, so often times they do rattle when they are shaken vigorously…unless you are talking about loose parts in the tube, but if that’s the case then it most likely wouldn’t have the correct voltages on the tube pins because something wouldn’t be making a connection in the tube.
Thanks for verifying that you tightened the tube socket pins. If you are pretty sure all the tube pins are making good connection then you don’t have to keep trying to tighten them. I just know in the past these symptoms have been caused by that.
You’ve probably already done this, but I wouldn’t hurt to double check the values of resistors in the signal path to make sure they are correct.
Please keep me posted with how things are going.
-Brach