[Milsurplus] ARC-5 Receiver and other tube questions

[John Hutchins]

Ray -

I have a 6V6 in metal Its for sale for a price ;-}
Hutch

On 2/17/2010 11:37 AM, Ray Fantini wrote:
> I always thought the metal case tubes were newer and better design then the glass tubes, the metal blocks inter electrode coupling, with a metal tube you don't need a separate tube shield. The old primitive BC-348 receivers used glass and shields where the newer series like the BC-348 Q used modern metal tubes not requiring exposed grid caps and tube shields. The ARC-5 stuff never evolved into anything requiring a redesign like the BC-348 did , the only thing I can think of is the late forties ARC radio equipment and think that all used metal tubes with the exception of the seven pin stuff.
> Question, why did some tubes stay in glass envelopes like the 5Y3 and the 6V6 for so long? Was glass a better heat transferring medium for hotter tubes? Cooler tubes like 6SK7 are hard to find in glass after the early forties but 6V6 stayed in production in glass almost forever. I have never seen a metal 6V6, where 6L6 was first a big glass tube then a smaller metal one, are all 6V6 glass only? What about the 6K6?
> Ray Fantini
> KA3EKH
>
>
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