[Amps] 807s

[Roger D Johnson]

Barry Kirkwood wrote:
> Nostalgia!
> the 6L6 beam tetrode hit the market around 1936 and soon after the works
> were packaged in a glass envelope with top cap and a 5pin base for RF use
> and designated 807.
> II recall a bit of interest in the 50th anniversary of 6L6 and 807 around
> 1986, guys buillt retro txs on breadboards using the tubes.
> BTW 6L6 also came out as a metal tube, and a variety of glass envelopes.
> Do not know when the 12v filament 1625 military version appeared. Think it
> would have been prewar. Think the ARC-5 receivers were in production mid
> 1930s, presumably the Tx that used 1625s late 30s.
> 807 variants I have met:
> The British type with ceramic base and British 5 pin base.
> Philips Dutch Q ----- version.
> The small envelope octal based version 5B254 ? that appeared in the late 40s
> or early 50s.
> The Brits had a similar beast with a loctal base.
> With the advent of TV the 6L6 was repackaged as a sweep tube ?6BL6 with top
> cap making it an 807 variant, I guess.
> Think this came out with a variety of heater voltages for use in series
> strings.
> Post WWII 807s were available cheap as mil surplus, 1625s even cheaper.
> So long as one treated the screen kindly they seemed to last forever.
> Back in VK and ZL when we were limited to 100watts input it was not unusual
> to see 807s in class C with 1000v or more on the plate, loaded to 100W in no
> problems.
> Also widely used in AM modulators and audio amps, sometimes triode
> connected.
> Great bottle.
> 73
> Barry ZL1DD

Another version we had in the URC-7 transceiver (US Coast Guard) was
a 2.5 volt instant heating version.

73, Roger


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