I got some teflon tape wrapped around the volume pot to isolate it from the chassis. That seemed to be the point of contact between the signal ground and chassis. Now when I touch the metal volume shaft, I get WLW clear as a bell. Pretty cool, Doug!! How did you manage to design that? The noise at full attenuation without signal has gone down quite a bit just by isolating the chassis, so I'm pretty happyI'm still chasing down the hum. I did the star ground off the volume pot's ground node, so this might be the problem. I'm going to move the ground point over to the inputs and use heavier gauge bus wire. I was using wire that was thinner than the in B+, except in the connection going to B-.
Hopefully all will be sorted out this evening. Now if I can just figure out how to tune in something other than WLW......Colin