@kijanki is absolutely correct. If a device has a plug with a safety ground, it's a Class 1 appliance and defeating the ground poses a safety risk. If you have a noisy ground, lifting the ground isn't the solution. Star grounding can help, as can devices such as the Granite Audio Ground Zero.
Cheater plug safety
So I recently decided to swap out my subwoofer amp for another one I had to see if it worked better with the driver. It did, but I have run into a slight problem. My old sub amplifier had a captive two prong cord. The new one has a 3 prong cord.
The subwoofer amp resides on a different AC circuit than the rest of the system. (Can’t be avoided)
Although the new amp is an upgrade for the sub, there seems to be a ground issue that is hazing up my transparency and sound stage. The system looses some air when the sub amps ground isn't lifted. There is no hum problem through any speaker per se, but just an overall sonic degradation when the ground is left in place. Using a cheater plug just on the sub amp brings back The transparency and it sounds absolutely beautiful.
I read that this can be dangerous, though. (Then why are these created plugs made?) anyway, I also read that as long as the amplifier with lifted ground is connected to the rest of the system via interconnect , and the other components are grounded, then the amp will use the ground from the other circuit that the other equipment is connected to and you are "safe", and only some very unlikely happenings, such as an internal ac wire becoming loose and touching the chassis and standing in a puddle of water should cause a concern. I even had a parasound 750 amp in my college dorm that even suggested using a cheater plug if needed for hum, sooooooo.........
At any rate I am addicted to the sound at the moment and going back without the cheater plug just sounds dull and fuzzy. The system is resolving and shows just about anything you do to it. Mind you, it’s not a night and day difference that would say that there is something wrong with any of the equipment, just a subtle but very tangible improvement that I definitely like and desire. The equipment is working 100% properly.....
It sounds so much better than the old amp and the transparency and air I’m getting right now are rediculous, but I don’t want to get shocked, but the chances seem to be very slim. Can anyone advise?
The subwoofer amp resides on a different AC circuit than the rest of the system. (Can’t be avoided)
Although the new amp is an upgrade for the sub, there seems to be a ground issue that is hazing up my transparency and sound stage. The system looses some air when the sub amps ground isn't lifted. There is no hum problem through any speaker per se, but just an overall sonic degradation when the ground is left in place. Using a cheater plug just on the sub amp brings back The transparency and it sounds absolutely beautiful.
I read that this can be dangerous, though. (Then why are these created plugs made?) anyway, I also read that as long as the amplifier with lifted ground is connected to the rest of the system via interconnect , and the other components are grounded, then the amp will use the ground from the other circuit that the other equipment is connected to and you are "safe", and only some very unlikely happenings, such as an internal ac wire becoming loose and touching the chassis and standing in a puddle of water should cause a concern. I even had a parasound 750 amp in my college dorm that even suggested using a cheater plug if needed for hum, sooooooo.........
At any rate I am addicted to the sound at the moment and going back without the cheater plug just sounds dull and fuzzy. The system is resolving and shows just about anything you do to it. Mind you, it’s not a night and day difference that would say that there is something wrong with any of the equipment, just a subtle but very tangible improvement that I definitely like and desire. The equipment is working 100% properly.....
It sounds so much better than the old amp and the transparency and air I’m getting right now are rediculous, but I don’t want to get shocked, but the chances seem to be very slim. Can anyone advise?
Showing 7 responses by cleeds
jetter ... does older equipment such as a Dynaco ST70 that has its original 2 prong plug have a greater shock potential? Yes, it actually does have a greater shock potential, because the ST70 was obviously a Class II device. This is why the three-prong, separate safety ground standard was adopted. The Dynaco is sort of like driving a '63 Chevy. It's safe to drive if it's in good repair, but it lacks seat belts, ABS and air bags. |
jea481mPerhaps you should read the code that you referenced: " A single receptacle must have an ampere rating of not less than the overcurrent device protecting the branch circuit." You cannot use 15A devices on a 20A circuit and be compliant with NEC. |
jea48 Trust me it does meet NEC code The NEC is updated every three years and the source you previously cited is 14 years old. Sorry, but using a 15A device on a 20A circuit is not compliant with current code. I don't doubt, however, that "it is done all the time." Perhaps you'll trust Bob Vila more than me. If so, read this. |
jea4811-07-2016 10:00am You can install two or more 15 amp receptacles, (a duplex is two), On a 20 amp circuit though.You can install a 15 amp receptacle on a 20 amp circuit, but you shouldn't and it violates NEC. A 15A device isn't rated to carry the 20A of current that a 20A branch circuit can deliver. |
erik_squires1m ... One 20A circuit may feed multpile 15A receptacles ...Strictly speaking, it is not safe. It is against code. Consider an improperly functioning 15A appliance that is now trying to pull 20A of current through the 15A receptacle. The 20A breaker will not trip, and the 15A receptacle will overheat. |
gbmcleod ... I've been lifting grounds for 35 years, and have not had a problem. From what I was taught (in High End audio), the ground should be at the preamp, and you lift the ground at other places.I agree with @eric_squires: you are defeating a built in fail-safe. Please don’t do it and don’t suggest it to others.It's simply hazardous to defeat a safety ground. Period. |