Re: signal leads that pick up less ambient noise?

On Fri, 21 Feb 2025 10:14:03 -0900, Christopher Howard
<christopher@librehacker.com> wrote:

I wanted to mention that this morning I moved the old PC computer box
about ten feet away from my work station, and that reduced the noise
down immediately to about 100 mV p-p, from the original 500 mV p-p.
>
After doing that, I tried running the signal from the signal generator
through a simple lowpass RC filter, with R=200? and C=1µF. This drops
the noise down some more to about 40 mV p-p.
>
I also moved the signal generator closer and am using some very short
leads with alligator clips. This doesn't seem to have much effect on the
noise, as far as I tell, but it seemed like a good idea in principle.
>
I like the idea of putting my analog computer inside a metal box, but I
don't currently have a spare metal box, and also that would hide all the
switches, trim pots, and terminals. I have an idea though of moving this
direction later after building some kind of patch panel. I also wonder
if it might be helpful at least to have the bottoms and sides of the
analog computer surrounded by metal, i.e., set it inside an open metal
box.

I found it essential to have a big die cast metal box with coax
connectors and low-pass feed-throughs mounted in the walls when
testing sensitive circuits.  A desktop faraday cage.  Plus lots of
coax cables between test equipment and the circuit within the box.

.<https://www.amazon.com/Hammond-Enclosure-Aluminium-Unfinished-Compliant/dp/9820858992>

Joe