mshilarious said:
The tube stage does not pass audio at the moment
DC voltage on all the pins is good, so I probably crossed a wire somewhere between plates and grids, or something. It'll have to wait for tomorrow.
OK, found that problem--the heater ground was not properly soldered
Fixed that, played around with it. It sounds pretty good, but as I suspected a few resistors are off. The first tube stage is getting hit too hard, so there isn't a clean tube tone available, and it gets way too distorted too fast. Actually when I looked at that, R50 and R57 (voltage divider going into grid) weren't done properly on the PCB, so they aren't doing anything.
Also I clamped down too hard on the second stage plate output, there isn't enough volume available from the tube stage. I'm gonna try 470K for R56 as a fix.
But my big problem is that my 12vreg keeps going into overload. I suspect it's because the transformer is putting out higher voltage than rated. Thus I have 37v on what is supposed to be 28v. That ends up OK for all components except that vreg, which is supposed to be max 35v input. I put some resistors in front of it, and the total draw should only be ~400mA, and I put a heatsink on it, but it hates me
It's my fault for trying to use the same rail for the bias and the heaters
Since there is no easy way to fix that vreg, I think I'm going to have to build a separate power rail for the heaters