15 Mar
2013
15 Mar
'13
10:07 p.m.
On 03/15/2013 09:28 PM, Josh Dersch wrote:
On the subject of tube radios, I picked up an RCA
Victor BP-10 awhile
back; this is a portable from about 1940 and it's actually pretty darn
tiny for a tube-based unit. (And it runs off a 63.5V B battery (#467)
and one D-sized 1.5V battery. Amazingly you can still buy the 63.5V
batteries new...). Anyway, I bring it up because aside from its small
form factor it has one other attribute I've never seen in a tube radio
-- it starts playing almost immediately (within a second) of turning it
on and the tubes never seem to get warm at all. All the other tube
units I've ever seen take 10-20 seconds to warm up first. Makes me
wonder a) what's special about this unit and b) why other units didn't
do the same -- seems like a pretty useful feature.
Battery radios were like that--since there was no indirectly-heated
cathode, it's ready to go as soon as the filament reaches temperature.
About the smallest vacuum-tube radio that I remember owning was the
Motorola Pixie. The Parrot was smaller, however:
http://www.radiolaguy.com/Showcase/PortableRadios/subminiature.htm
The funny thing was that for my first transistor experiments, I used
submini tube sockets instead of harder-to-get transistor sockets.
I used pick up surplus computer boards (I think they were military) that
had 6 submini dual-triodes (usually) on them, in clips running on either
size of the PCB in the middle. They were actually pretty useful in HF
circuits.
--Chuck