[Tubesforme]

With all the tubes in place, try grounding the grid of the 27.

Steve

When grounding the grid of the 27 audio tube, the hum disappears completely.

I also used a 4.7uf/450V capacitor and connected the + to ground and the - to the grid. This too kills the hum but also the signal.

Byu the way I again checked the detector voltages using the cathode as the common point and the voltages on the tube didn't change.

Any other good ideas?