DIYbanter - View Single Post - What's the latest in Desoldering gadgets?

Jon Elson[_3_]

wrote:

On Fri, 24 Feb 2017 16:11:20 -0600, Jon Elson wrote:

No, certainly not! You use the modulator from an old AM broadcast
transmitter. I was at a Grateful Dead concert in 1969 and they wheeled
out this THING on the stage with big glass globes, and when they lit up I
realized they were TUBES (valves to the British)! Not sure of the type,
but
at least several thousand Watts. I borrowed a set of ear muffs and sat
back for a show!

Jon

I was at several Grateful Dead concerts in the late 60's and afterwards.
I never saw any such thing. Are you sure you were not "tripping"? That
may have just been a common 6L6 tube in a guitar amp, and your
hallucinations made it look really BIG....

Nope, this was at the Fox Theater in St. Louis. Yes, there were certainly
some people tripping on various substances, but I was not. I can't prove it
was an AM broadcast modulator, but I can't imagine any other package that
would look like that and be available as a unit. There was even an article
in the local paper about that event, and how the band had all their
equipment confiscated for non-payment, and had to scramble for gear the day
of the show. I seem to recall Bob Heil came to the rescue and loaned them
this equipment.

Who ever heard of wearing earmuffs at a Grateful Dead concert.....

Only, me, I assure you! I protect my hearing, that's why I still have most
of it.
And since you mentioned it. What the hell is wrong with them British?
Valves are plumbing parts. Tubes are electronic parts!!!

yeah, they have funny names for EVERYTHING that was invented since 1776.
side curtains (side windows)
bonnet (hood)
accumulator (car battery)
boot (trunk)
gear change (gear shift)
and there are plenty more...

Seriously, I have heard of using AM transmitter tubes for audio amps. I
dont know what those tubes are numbered, or how much power they output,
but I know that many AM radio stations have power output in the
thousands of watts range. But to use that kind of tube would require
custom output transformers that would likely mimic the pole transformers
used to feed our homes....

Well, I'm no expert, but apparently the modulation transformer does a pretty
fair job of being an audio output transformer. I'm guessing there may be
some change to the output winding to lower the output impedance, or else you
just wire a bunch of speakers in series. And, don't ANYBODY touch that rig
while it is running, it could be lethal!

Jon