Hi Thanks for that, I seem to have got the type wrong
its from a AN/GRC-9 so I'm told
I'm pretty sure I must have the volts and connections wrong
somewhere, there are two pins I'm not sure of, pin 4 seems
to be the HT feed to the Audio Amp and pin 5 the HT for the
rest of the set, I have joined them together and fed them with 90v?
The noise is just plain Hiss, background hiss on everything
I can't seem to get a nice quiet signal even though it seems
quite sensitive, yes the valves are quite mikey, I don't understand
the volume control either, why is it dual ganged? is there some
sort of AGC control involved?
from Ron...


On 28 Oct 2003 05:29:59 GMT, r (Mike Knudsen)
wrote:

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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