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

[Jim Beacon]

From: "Tony Duell" <ard at p850ug1.demon.co.uk>


> > If things had worked out differently we might be using
> > ultraminiature electron tubes. Imagine! An entire flipflop in one
> > package!
>
> I nthe 1920's, Lowe (in Germany) made a radio receiver which consisted of
> a tuend ciruit, headphones, batteries, and a single glass envelope. That
> contained 3 triodes and all the R's and C's.
>
> The idea did not catch on. The single glass device was expensive, and if
> any part failed you ad to replace the whole thing. Other radios were much
> cheaper to repair.
>
> A flip-flop valve would certainly be possible.
>
> -tony
>

The Loewe idea was a tax dodge, at the time, UK tax was levied on each
valve. By placing the three devices in one envelope, then only one lot of
tax was incurred, which made the device cheaper than three seperate valves,
unfortunatly, reliability was only 1/3 of that of a single valve(I know I'm
oversimplifying, but I've had a long day and can't be bothered with the
maths.....), consequently, the set became more expensive to run than a set
with three seperate valves.

In terms of general valves, it was not unusual to find 4 seperate devices in
one envelope at the end of the valve era, eg the EABC80, which is three
diodes and a triode, used in the detector / 1st AF stage of VHF FM sets in
the late 50's. ISTR that RCA made some impressive multi element valves for
TV use, with 3 or 4 devices in one envelope, but they used a special (13
pin?) base - there are a couple of designs for AM radios that will drive a
loud speaker, but only have one piece of glassware (I wish I could remember
the RCA name for the devices...).

Jim.