v-mid slight progress

So I built a copy of the "v1" v-mid EQ circuit on a separate board, as discussed earlier.  But when I patched this into the amp, no joy.  There was no sound passing through at all.  Initial circuit tracing didn't find the problem.  So I took some time out to step up my troubleshooting game.  I built a 555-based tone generator for signal tracing, I ordered a cheap Chinese digital oscilloscope online, and I built a general-purpose tube circuit test fixture.  Running the v-mid board standalone in the test fixture, I was able to trace it out with the scope and discover the wiring error which was leading to no sound.  So now I have it roughly operational, which is a big boost to my sanity!  However, some more work is needed before I can try to fit this circuit board back into the amp -- which will be a challenge in itself.

Next task when this is done, will be sorting out the effects loop.  It's been several months of setback and delayed progress now, but finally I think there's some light at the end of the tunnel.

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