Thanks for all your replies.
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?
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- 45 posts total
audiolover, Hopefully the responses posted on this thread answered your questions in your original posted message. Just a guess you will continue to use the ground cheater on the sub amp because it eliminates the ground loop hum. You are not the first to experience a ground loop hum problem with a subwoofer amp, that uses a 3 wire cord and plug, and you won’t be the last. Jensen transformer does make an isolator you could install between the preamp and the sub woofer amp that should/will break the ground loop circuit, thus eliminating the ground loop hum. If you are worried about it degrading the SQ of the sub I doubt with the Jensen isolator you would hear any difference. http://www.jensen-transformers.com/product/sub-1rr/ I would recommend the Jensen transformer isolator over the ground cheater. But if you must use the ground cheater a GFI receptacle in place of your existing wall duplex receptacle would be a safer option. You could add a level of personal protection from any risk of a life threating electrical shock by changing out the existing wall duplex receptacle outlet to a GFI. A GFI receptacle does not need an equipment ground to function/operate as designed. Just buy a good GFI duplex receptacle outlet, not one of those really cheap ones. I have seen the cheap ones fail and not trip open when called upon. Leviton makes a pretty good GFI duplex receptacle. If you do decide to change out the existing duplex receptacle to a GFI replace the old one with a GFI of the same ampere rating. So if the existing is a 15 amp, more than likely the branch circuit is a 15 amp, you must use a 15 amp rated GFI duplex receptacle. You cannot install a 20 amp receptacle on a 15 amp branch circuit. A 20 amp receptacle can only be installed on a 20 amp branch circuit. You can install two or more 15 amp receptacles, (a duplex is two), On a 20 amp circuit though. . |
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. |
In order to make my Dynaco st70 safe to use, I would need to have a three prong plug attached? Easy to have done, but just asking if that is the solution?No- not saying you can't do it, its just that its more complex than that. The amp employs some chassis grounds that would have to be modified. This is the sort of project that should be done by someone that understands Class 1 grounding and also understands the significance of ground loops. |
@cleeds I in this case I believe you are mistaken. :) One 20A circuit may feed multpile 15A receptacles. For those who don’t know, the 20 A receptacles look just like a 15A but with one leg T shaped, allowing for either 15A (normal) or 20A plugs. More here: http://diy.stackexchange.com/questions/12763/why-is-it-safe-to-use-15-a-receptacles-on-a-20-a-circui... It’s perfectly safe to put a 15 A receptacle on a 20 A circuit, but it won’t have the T socket for 20A devices. In residential use these are actually pretty rare. |
- 45 posts total