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Is this a "death cap"? (Ampeg VT-40)
Old 26th July 2020
Gear Head

Is this a "death cap"? (Ampeg VT-40)

Hey all, I have an early 70s top-load Ampeg VT-40. Trying to learn and do some initial service work, at least as much as I can, starting with replacing the cap cans and putting in a 3-prong power cord.

This amp has a polarity switch and a corresponding capacitor which I first assumed was a "death cap," but looking at the schematic I am unsure.

I've done a little bit of work with old Fender amps and I had always understood the "death cap" as going straight to ground.

In this schematic (attached), it's not. Should I still remove it when I install the grounded power cord? If not, any ideas how I should wire it while bypassing the polarity switch?

Thanks so much for any help!
Attached Thumbnails
Is this a "death cap"? (Ampeg VT-40)-vt40powerwiring.jpg   Is this a "death cap"? (Ampeg VT-40)-vt40powerwiring2.jpg  
Old 27th July 2020
Lives for gear
enorbet2's Avatar
Yes. That ( C20 ) is what is commonly referred to as The Death Cap. The truth is that it is only of some potential danger depending on parts quality. Ampeg used a 600V cap there so the likelihood of actual death is very low as it is roughly 3 times even 220vac systems. It's not going to short. Still, it's just wiser to replace any 2-prong/2-wire power lead with a properly grounded 3-wire. A LOT of people used such amps for a LOT of years and I only know of 3 deaths. So the odds are in extremely low percentile that you would die BUT no matter how infintessimally slim the odds are, why not just make them Zero? It does not affect operation or tone to do so.
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