Wanted: vacuum tube logic circuits - test-drb@ccmp.vtda.org

30 Aug 2008

William Donzelli wrote:

...
  I have exactly one 12U7 in stock. I have a few
 12K5s, as  well.

  I've now got a number of different dual triode  tubes to try from a local
electronics shop that has a large
 collection of tubes from former TV and radio repairmen.  $1
 each and they have a B&K 707 tube tester to test them
 on.

 Well, in case you wanted proper space charge tubes for your
 digital logic experiments. 
Oh, now I understand, thanks.  Well, there were a few space charge tubes in their $1 bin
and they had six of the coveted (for audio) and relatively rare new old stock 6GM8s in
their new tube section that they sold me for $3.75 each (they didn't know what they
had) which was their cost in the 70s.  They were trying to clear out their extensive new
tube inventory of types that they hadn't sold for quite some time.  With a car radio
tube like the 6GM8 that is now of interest primarily to tube audio hobbyists, I can see
why they hadn't sold one in a _long_ time.