21 Apr
2005
21 Apr
'05
12:29 p.m.
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.