|
Upon further inspection, I discovered that this amp is a "hot" chassis design. In later years, there was an isolation capacitor between the chassis and circuit ground. On this model, everything is grounded to the chassis. The cartridge ground terminal connects to the metal cartridge body; which, is attached to the metal tonearm. Depending on the position of the AC plug, that would make the metal tonearm "hot". If someone was in contact with ground and touched the metal tonearm at the same time, the result could be fatal.
Installing a polarized AC cord would be fine, unless the unit was plugged into an outlet that is wired backwards.
So, my option is either to redesign the amp with an isolation cap between the chassis and circuit ground. Or, install an isolation transformer inside the unit. I wanted to keep the design original; but, safety is more important.
I removed the old cartridge and the leads actually solder to the cartridge; which, is rare (especially for a crystal type). Even with the cartridge removed, the tonearm weight is likely still too heavy for a current cartridge and I see no easy way to counterbalance this arm; so, I guess I'll be rebuilding the old cartridge.
|