[Bob Carriere]

Hi David

You would think that the availability or number of spare valves would be determined by actual front line or training experience yet the PS has 3 identical valves and there are not 3 spares...... when I read on replacing these valves they strongly suggest testing them so that the output parameters are matched or as close as possible. Maybe matching valves for output is a peace time luxury and in real front line you keep replacing tubes until the set works.....

Or could more than one spare box of valves be carried........

My dad who in the fifties ...use to service radios and early TV and he had a tester which I believe he used to identify really dead tubes or impress customers ( remember they did house calls in those days )...bottom line you replaced tubes until the set worked again...even good ones on the tester did not mean 100% the set would work...or again a matching issue with other valves in the set.

I have acquired a few good military testing units that actually assess outputs but you still verify the reading of one tester against the reading of the second tester to be sure......then you have good valves that are loose in the bakelite sockets which reads as good....... or loose pins!!!! always been tempted to leak a few drops of crazy glue in the sockets to salvage some good ones...... I even have sockets that fits in the tester sockets to save on wear and tear of the testers and to straighten pins.

Still quite a stock still available on Ebay particularly source from behind the iron curtain (former USSR ) where I believe some are still being produced. I visited a private residence of a guy in Ottawa who purchased the total stock of a shop that was closing..... he had upstairs bedrooms in a very nice house... filled with shelving units and tubes from floor to ceilings and spare cardboard boxes for the tubes....... YES he was widowed and lived alone!!!!!

I remember my dad throwing out some of the early 20s huge valves which we used as grenades when playing soldiers... they popped real nice.....what a shame.....

Bob C.