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What am I Doing Wrong?

WntrMute2

Super Member
and how do I fix it?
Trying to determine whether this pre-amp I built is working properly. I cannot seem to get a trace on the O'Scope that seems meaningful. I can get a great trace running the Signal Generator directly into the scope but with the same settings, the pictures show what is displayed. I've used the auto feature a number of times as well as trying manual setting the scope.
I have a new Rigol scope and a new BK signal generator and the tracing I'm getting is just without meaning!

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It looks like an oscillation. Do you get the same display with no input? Does the volume adjust affect it at all?
 
As an experiment, just shut off the preamp's power and see if the noise on the scope goes away. Don't touch anything else in the setup. I had an instance where nothing happened when I did that. The noise was getting in as a ground current in the scope probe's shield lead.
 
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