Another cheater plug thread

09-11-12: Newbee
Don't the rca's connecting the CDP to the pre-amp effectively ground the CDP chassis?

Not necessarily.

A good design will often have circuit ground and chassis connected together through a low value resistor (to minimize ground loop susceptibility, compared to having them connected directly together). That creates an excellent chance that the resistance will reduce the amount of fault current (that would flow from the CDP's "hot" chassis through the return conductor of the interconnect through the resistor to the preamp's AC safety ground) to a level that is too low to cause the breaker to trip. The result would be that the resistor and/or the interconnect and/or anything close to them might go up in flames. The resistor would most likely burn out, in any event. Then when the user comes over to investigate, the hot chassis would still be hot.

Sometimes high current diodes are paralleled with the resistor (as is a capacitor, for RF filtering purposes), to prevent those possibilities. But I wouldn’t count on the diodes being present.

Also, if the user is connecting the CDP or other component having a hot chassis into the system while it is plugged into the AC, and with one hand he touches either the hot chassis or the ground sleeve of an RCA connector on an interconnect that is connected to the CDP and is about to be connected to the preamp, while touching the chassis of the preamp (or anything else that is grounded) with the other hand, 120 volts would be placed across his chest and arms.

Unlikely? Yes. Inconceivable? No.

Best regards,
-- Al

Newbee, Interconnects make connections between signal grounds that most likely aren't chassis grounds.

If your chassis is NOT grounded to the wall outlet ground it will be floating above ground. With a VOM set to continuity, touch the chassis to the wall oulet "ground" and it should measure continuity showing it is indeed grounded. Removing a chassis ground might break a ground loop and sound good but it is deadly if you touch the unit's chassis, and any conductor to ground. If there is a fault in the system, the system is looking for a ground through YOU someday, and to earth. THAT is WHY the chassis has to be properly grounded at all times.

I would heavily advise to not let your chassis float ungrounded, and fix the ground loop.

Removing a chassis ground might break a ground loop and sound good but it is deadly if you touch the unit's chassis, and any conductor to ground.

Amend to 'could be deadly'. Its that 'could' that is why there are things like UL and CE directives.

In the old days the RCA ground was the same thing as chassis ground in a lot of cases. IMO that is a bad move, and the better manufacturers even in the old days avoided the practice.

The funny thing is that proper grounding also results in better sound. You would think more manufacturers would want to be on board with this....