Balanced power and 2 prong plugs

I have a question regarding using balanced power on my vintage Macintosh MC 60s. I have balanced power on my front end and have an opportunity to purchase an Equi=Tech unit for my amps. My concern is that with a 2 prong plug, the power cord lacks the third line to carry the ground. Will the balanced power unit still be effective?
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The Equitech website is very informative.
Hi Dent,

The 3rd prong is not used in power transmission. It’s role, when equipped, is to ensure the metal chassis of your equipment is ALWAYS at ground potential. Should a short occur between the power supply and the metal chassis that pin should short it to ground, causing a breaker to trip. The alternative in these cases is that you, your pets or your children become the short to ground when you touch it.

Devices that do not require a third pin are double insulated, or do not have a metal exterior chasis. My subwoofer is like that. The external parts are all wood.

The balanced power benefits will help your entire system no matter which of these devices you use. That is, 2 or 3 prong. However, there are arguments that balanced power devices don't always help with ground loops. I've found the best way to deal with GLs is to add isolation to the offending devices. Usually this is a Cable TV input, or PC audio input.


Hi Eric,

Your contributions to the forum here are quite informative and much appreciated. System is quiet as to ground loops but the hash during the day probably contributes to a degradations in sound. Hi efficiency speakers suffer more from bad power, no?
Always on a quest to quieten the noise and thought the Equi=tech unit might do the trick on amps. Appreciate the info.

Ptss, will check that website as well, thanks
Also remember you can always phone Equi=tech and speak with someone that is knowledgable.

I hear you. The Equitech will reduce noise just as much for 2 prong as 3 prong devices.

I can't afford anything that expensive, so I use Furman with LiFT instead. It's effective enough, and expensive enough for me. :)




From what I have been able to find out about the MC 60 mono amp it does not have an AC noise capacitor installed on one of the AC 120V lines, that feed the power transformer of the amp. If it had I would have not recommended connecting the amps to a 60V 0V 60V (split phase) Balanced power system.

If it had the noise capacitor, even if you plugged both amps into the balanced power unit so the plug orientation would have been the same you still would have had a 60Vac potential to earth ground on one of the two hot AC power Lines, legs, that feed the power receptacle/s. Also depending on the preamp or any other piece of audio equipment connected together by wire ICs, that use a 3 wire plug using the safety equipment ground, there is a possibility enough leakage current would pass through the AC noise capacitor to chassis and cause the GFCI (Ground Fault Interrupter) on the balanced power unit to trip open. Like I said though, it seems your MC 60 amps do not have a noise capacitor installed on the AC line.

I believe this is the wiring schematic diagram for your MC 60 amps.

No on/off power switches on the amps?

This AC forum link may be of interest to you. I did not read through the entire thread, only page 1.


Hard to believe a year and a half has passed. Erik, I finally found a Equi=Tech wall unit, had it installed about a month ago to good effect. Deeper quieter and more dynamic. Good advice from you and jea48 and much appreciated.
Used Equitech units don't come up for sale very often, lucky you ;-)