Alternating audio signal added to run simulator. Left side is signal input with probe on top line and connector clip on ground. Leads on right are for guitar plug into small guitar amplifier. SPDT switched right is audio tracing and switched left for RF signal tracing. Top capacitor is 10 nF and bottom capacitor is 47 nF ( both capacitors are 630WVDC). Diode is 1N34A and resistor is 2.2 M ohms.
Always use isolation transformer if signal tracing at line voltages.
I would think other amplified speakers could be used as well.
Video link shows how well this circuit can work:
https://www.youtube.com/watch?v=QUmPBBnzkRE&feature=em-subs_digest
