[Milsurplus] BC-9: Earlier and Later Operating Instructions.

Mike Morrow kk5f at earthlink.net
Mon Feb 13 03:16:47 EST 2017


Ken wrote:

> From the similarity of the circuit AFTER the oscillator tube,
> I suspect that the two transformers, T-2 and T-3 are simply
> common 3:1 transformers.

Ken, there is no T3 in the BC-9-A.  There are two T-1 and one T-2 AF transformers.  In the BC-9-* schematic, all identical components got the same designation...hence two T-1s, two R-2s, and two R-3s.

T-1:  Signal Corps Coil C-21, 1:4 (plate:grid) turns ratio.
T-2:  Signal Corps Coil C-57, 1:1 (plate:hi-z headphone) turns ratio.

Mike / KK5F


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