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Premature judgement

So, when I reported a 90% improvement, I hadn't yet moved all of the current sharing resistors to the safe side of the PCB. Three out of 8 were still on the sensitive side of the board. I finished the job yesterday and was hoping the result would be a small further lessening of the noise, which I am measuring by AC voltage on various parts. To my chagrin, that is not the case. In fact, after moving those last 3 resistors, the measurements are not quite as good as they were yesterday. I changed nothing else. It's not a complete regression, but not an improvement either. And for all I know, the amplifier would "work" if I connect it back to the speaker. It's getting to the point where I have to just try it.

I have one more trick to try first. Years ago when he was also trying to eliminate oscillation after I first purchased the system, Bill Thalmann put some ferrite beads on the leads of the 1K grid stop resistors, on the side nearest to the low voltage input stage. When I moved the bodies of the 1K resistors closer to the grids of the output tubes they serve, I also moved those ferrite beads closer to the HV output board. I wonder whether THAT is now contributing to the random noise. I will move them back toward the input board and see what happens.

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