[sdiy] radio distribution (was: bio electricity)

[Alex Stettler]

Hi,


We had this system of radio distribution over the telephone network here in
Switzerland, too. It was called "Telefonrundspruch" (Well, at the moment
I really don't know how to translate this, so I leave it as is ;-).
It was taken out of service only some years ago.
It was mostly used in older houses, hotels etc.

Alex

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Dave Krooshof
Sent: Monday, November 05, 2001 10:35 AM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] bio electricity


>Do you remember the FM audio distribution allong the
>home mains power lines?
>
>m.c.

Yes, I do. That is: Im too young to remamber, but I have the equipment.
Here's a last weeks email pingpong from Harry and me.
Maybe you can shine another a light on the safety issues...

_________________________________________
--- Dave Krooshof <krooshof at xs4all.nl> wrote:
> A tube question, Harry,
>
> I happen to have a 3 tube amp from the Radio Distribution.
> That was a thing from the fifties, when the Dutch Phone
> company used the telephone lines as a radio transmitter.
> In the house was a box mounted on the wall. It had a switch
> to choose between 5 chanels. Then it had a switchable trafo
> for volume. The amp is totally weird. It hasn't got a trafo, nor
> for the power supply, nor for the speaker. No readable info
> anywhere on the print, parts, or box.
> The odd thing is... I connected a jackcable to its input.
> When I touch it, it doesn't hum, it beeps. Even louder when I lick
> the plug. And it's tunable with a crybaby (not with other wah's).
> Then I make beating patterns with a flanger and a chorus.
>
> What is your guess, what happens in the amp?
> AM?

My Guess... it may be a transmitter, probably AM if its from the
50's... FM was just getting started and not common yet.

Probably rectifies the line directly for HV, and runs the filiments
in series (maybe 3 tubes @ 12V each... 36V... then some resistor
in series so it don't blow.
Is there an incandescent lamp anywhere... pilot light
maybe... that could be part of the dropping circuit.

> And can there be any danger that one day 240 volts
> will hit me when a tube decides to break down?
Yes...  I would not lick the plug too often....

Y'know it might use a series capacitor to drop the voltage to
the filaments...
anyway... its dangerous. I only lick 9V batteries, tops... and I'd
transformer isolate AND ground lift if I was gonna do it on stage...

<video cue... cartoon electric shock... where the body flashes yellow
and black, and you can see the bones inside... >

H^) harry


>
>
> Dave