[Eeyore]

Bret Ludwig wrote:

Eeyore wrote:
Bret Ludwig wrote:
Stuart Krivis wrote:
On 25 Sep 2006 12:51:12 -0700, "Bret Ludwig"
wrote:

Triodes are cheaper to build than beam power tubes of a given size,
simpler, and can be used for amplifiers of any size. Most 50 kW AM
broadcast transmitters had two triodes in their modulators giving 30 kW
audio power in Class B.

AM transmitters are a bit orthogonal to the topic at hand. :-)

Don't MAKE me get Allison on you! Every one had a BIG AUDIO AMP. Else
you would have had nothing but Morse code.

And since when was AM 'hi-fi' ?

That would be before VHF FM became dominant. On days with little
electrical storm activity in the hemisphere and in the right locations
very fine broadcast fidelity was possible. Even today, at a place I
visited in north central Missouri I heard KXTR from Kansas City through
a passive Millen tuner (essentially a crystal radio) in astonishing
fidelity at an elderly hi-fi buff's house. Shame everything they play
is by the appalling Sir Neville Marriner at the Academy of
St-Martin-in-the-Fields. Vintage Toscanini and other classic
conductors' recordings would be so much better, but instead they play
that LOAD continually.

They say LF transmissions in England and Germany were even more
impressive.

The problem with AM AUIU was always one of bandwidth for one part and of course
that any interference was directly demodulated.

Those old valve sets did sound rather good though ( I had one myself - an EKCO !
) but that for the most part was mainly due to the excellent design of the RF
circuitry.


Graham