[ARC5] Tube B+

[Bill Cromwell]

On Sat, 2013-03-09 at 11:59 -0500, Wayne Eleazer wrote:
> I have run my ARC R-11A at a B+ of 28 VDC and it still worked.  Normal
>  B+ for that receiver, is of course, 250VDC.
> 
> Wayne 


Hi,

I am on several mail lists that feature use of tubed radio gear at least
in part. Quite a few of the members report successful use of reduced B+
on tubes that were not specifically designed for low B+ (space charge
tubes). I have used a ~45 volt battery as B+ for the command receivers
that have weak caps with some success. When the caps are replaced they
are just that much better. There are some places where I can get a six
pack of 9 volt batteries for just over six bucks making them more
affordable as fodder for tube rigs than the five dollar individual
batteries with the gold plating and rabbits for salesmen! I don't think
any kind of a transmitter would operate very long on five of those! But
receivers can be much more thrifty with B+. I build my AC receiver power
supplies to target anywhere from 90 to 150 volts.

There are some fellows on one of the regen lists who operate their
radios with B+ as low as 6 volts! 12 volt B+ supplies are reported quite
a bit. Those guys use more B+ to get speaker volume but can use the
audio with earphones at those same low voltages. Some of them resort to
solid state audio power for more oomph without higher B+. Some people
have trouble keeping their fingers out of the B+ and low voltage
operation is real attraction to those guys (evil grin). I can test a
single 9 volt battery with my tongue but I like to have enough of them
(at least five in series) that I don't want to test that way! Here...
hold these wires (evil grin).

Maybe one of these days I'll try a single 9 volt battery as B+ on one of
my command receivers just to see what happens. Now if we could do
something about that heater power requirement...

73,

Bill  KU8H