[Milsurplus] more tube stuff! Now: BC-1206-CM, R-76/ARR-13

[Mike Morrow]

Jack wrote:

>I think you will find that the R-76/ARR-13 used "real B+" voltages, on the
order of
>250 or so.  Unlike the BC-1206, the R-76 has a 4 pin Jones plug with
filament and B+
>brought out separately.  I assume that it used something like a PE-86 for
power.

Very good info, Jack.  I stand corrected.  I have never fired up my R-76,
and I assumed it used 28 vdc B+like its kin.  I even thought it used the
same tubes, lacking a manual for the AN/ARR-13.

But the tube line ups are rather different, even though the physical layout
is almost identical for the two receivers below.

                              RF    Conv     IF       Det/Aud      Aud
R-76/ARR-13    14A7  14J7   14A7      14B6      14A4
(Stetchell-Carlson Model 512)

BC-1206-CM    14H7  14J7   14H7      14R7       28D7
(Stetchell-Carlson Model 524)

Only the 28D7 in the BC-1206-CM, of all the tubes listed for both receivers,
was designed for low plate voltage operation.  I wonder if the R-76/ARR-13
would have worked nearly just as well with a 28 vdc B+ supply instead of
some higher value provided by who knows what power unit (PE-86 sounds like a
good candidate).

This has me wondering which receiver came into service first.  Model 512
would seem to be earlier than Model 524, yet Model 512 bears the more modern
JAN nomenclature and has the 278 kc fixed frequency select button.

All this is just extreme trivia, yet it's interesting to some (me).

73
Mike / KK5F