RE: Old amps, was Re: Far out man!

[Edward_Chang@mail.amsinc.com]

At this point I'm getting nervous about this tube-powered turntable wiring.
How do detect a hot chassis?  Can I do that with  a multimneter?
Up until this point I've been wiring the cartridge leads directly into
output jacks, disconnecting them from the circuit boards completely.
Somebody had mentioned that turntable circuits have some eq built in to
"normalize" the cartridge frequency output, which is why I wanted to try
the speaker outs, but it doesn't sound that bad with some mixer eq anyways
(and I'd hate to have a shocking revelation).  We'll see.
But the idea about the potentiometer sounds good, can I use that same
technique for battery operated toys, like Casio keyboards and hand-held
video games, etc...?  That sounds safer at least....to be honest, I'm
pretty much a beginner so I'm trying to do things a little at a time....
Again thanks for all the help!

Ed


Dave wrote:




Dave Stagner <dstagner@icarus.net> on 09/02/98 01:10:59 PM

Please respond to Loopers-Delight@annihilist.com

To:   Loopers-Delight@annihilist.com
cc:    (bcc: Edward Chang/AMS/AMSINC)
Subject:  RE: Old amps, was Re: Far out man!




Alan raises a good point about the possibility of a "hot chassis"... and
if he's right, you should not use that turntable in a circuit with any
other audio equipment.  It's a hazard to EVERYTHING.  You can possibly
isolate it using a low-current isolation transformer, but ultimately it is
a very dangerous piece of equipment.  Even in high-voltage tube amps (a
tube guitar amp can have upwards of 500v!), the most dangerous part by far
is the AC mains.  Power transformers limit the heart-stopping current.

For more on electrical safety when working on tube amps, check out
http://www.bottlehead.com/valve/safety.shtml

-dave

Practice beautiful randomness and act kind of senseless.
<dstagner@icarus.net>