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

[Dave Stagner <dstagner@icarus.net>]

On Wed, 2 Sep 1998 Edward_Chang@mail.amsinc.com wrote:

> 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?

The way to detect a hot chassis is through examination.  The power cord
should lead to a power transformer inside the chassis, with multiple leads
from that transformer to the tubes and power supply parts.  If the power
cord goes directly into the circuit without a transformer, you have a hot
chassis.  

> 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.

RIAA equalization for turntables provides both eq and gain.  Cartridges
don't have much output.

> 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!

For modern solid-state electronics like Casio keyboards, this extra
complication is not needed.  Just take the speaker or headphone out and
plug it into the input of your mixer or guitar amp, and use the on-board
volume controls to manage the volume.  The line-out box i've suggested is
only necessary for tube amps, which are extremely sensitive to their load. 

-dave

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