RadioBanter - View Single Post - Help with GCR-9

October 28th 03, 05:29 AM

In article ,
(Ron) writes:

I recently bought an old Receiver from out of an old
GCR-9 I have no info other than a circuit pasted into
the bottom plate, I have hooked it up with 1.4volt
heaters and 90v HT also there seemed to be a 4volt
Battery that didn't seem to do much on the grid of
the audio amp is that correct?

You do want that -4V of grid bias on the audio amp grid. The good old ancient
"C" battery from the 1920s seems to have made a comeback in this set :-)

The receiver seems quite noisy is this usual for these
old receivers? I can't find anything obviously wrong
but I have little experiance of these 1.4volt tubes

"Noise" would be the usual suspects -- resistors, capacitors, and of course
dirty tube sockets and pins. But those 1.4V tubes are notoriously microphonic,
and will sing out with a "ping" each time you bump the chassis or flip a
switch. Sometimes a tube will just start singing on its own, with feedback
from the speaker. Replacing tubes or swapping identical types around in the
set may help.
73, Mike K.

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