OT Don't read this crap, aka vacuum state

[Tom Jennings]

On Wed, 20 Apr 2005, William Donzelli wrote:

> Integrating the functions, like in the Loewe tubes, never caught on. In
> the US, a few directly coupled triodes were produced (6N6G being the most
> common), and some of the eye tubes had a built in triode as a driver, but
> for the most part, each function was pinned out individually. The most
> advanced integrated tube was probably the VT-158 Zahl tube - a 600 MHz
> pulse oscillator in a bulb. It was a dead end.

The compactron type tubes designed specifically for TV sets were
as close as successful "integration" got, combining common
adjacent stage active devices into one envelope, but it was a
commercial tuning of course, nothing particularly innovative
(other than the inexpensive (sic) Compactron package). It's not
that new either, dual-diode/triodes (FM det plus first audio) are
old hat.

In hindsight, it seems pretty obvious why "high density" never
caught on -- cathodes and filaments die, tubes were expensive.
Packaging tubes is expensive.