OT Don't read this (was Re: Altair MBL source)

[Tony Duell]

> Certainly, multifunction tubes were around - the first ones were the dual
> diodes and rectifiers of the 1920s, then later twin triodes, extra diodes,
> and yes, to the ultimate Compactrons.

The most complex common multi-section valve in the UK (i.e. with the most 
sections), is the triple diode triode. It came with a variety of heater 
ratings -- the EABC80 (6.3V heater), UABC80 (100mA series string heater, 
by far the most common version) and the oddball PABC80 (300mA series 
string heater). It turned up in numerous AM/FM radios in the 1960s, where 
it was used for the AM detector (1 diode), FM detector (the other 2 
diodes) and audio ampifier (triode). It has a B9A (9 pin miniature) base, 
so there must be some commoning of electrodes going on, probably the 
cathodes.

-tony