twiiii
Lunatic Member
It was a common problem your experiencing back in the late 50's and 60's until polarized two prong plugs and polarized wall out lets were available and being installed. My appartments in the 60's and my homes and parents homes all had non polarized outlets. So after I got m License I replaced all the duplex out lets with grounded polarized outlets. Remember your 120 volt source one wide spade or slot is the neutral and the narrow one is the positive. And though the neutrals are supposed to be tied to ground in the circuit breaker box any compromised connection can cause issues. So there fore its important you have the correct polarity using the older 240's with non polarized plugs to keep the lowest potential of the chassis of the amp. Having another component that is full grounded either by use a 3 pronged ac plug or where the unit is grounded to an external ground will present you with the issue you are experiencing. Its was common practice to make sure all the plugs of your system were plugged in properly in the 60's and late 50's. This reduced extraneous hum and reduced hum, too.
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