[Collins] 6DF5 pin #7 not used in 75S3B?

[Dr. Gerald N. Johnson, electrical engineer]

The tube grid is hooked to both 1 and 7. Doesn't matter which is wired
at the socket.

I found background AC hum in my 75S3B from hum modulating the noise
through the mechanical filter. I added a magnetic shield to cure that
back about 1965. The other hum source was a little heater cathode
leaking in the notch Q multiplier tube.

73, Jerry, Technical Advisor to the CRA.

-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.