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Grounding problem with Lepai Class-T amp, please help.

post #1 of 4
Thread Starter 

(X-posted from headphone amps)


I really like my new Lepai Tripath Class-T amp (http://amzn.to/W9fPmF) but it produces a high pitched whine that really ruins it. When I touch the outside box it somewhat decreases. This makes me think it needs to be grounded. It takes a 12V adapter. Is there one that will ground it? I know a little about electronics, how could I ground it myself?
Thanks!

post #2 of 4
Quote:
Originally Posted by PascLeRasc View Post

(X-posted from headphone amps)


I really like my new Lepai Tripath Class-T amp (http://amzn.to/W9fPmF) but it produces a high pitched whine that really ruins it. When I touch the outside box it somewhat decreases. This makes me think it needs to be grounded. It takes a 12V adapter. Is there one that will ground it? I know a little about electronics, how could I ground it myself?
Thanks!


I do not know if my HUM ground noise is the same with your problem or not but I own a few of the Lepai 2020+ and I am very happy with its SQ and build until I found out that they have ground hum.

 

At first 2 of my Lepai 2020+ produce a loud ground hum starting from 9 o' clock on the volume pot. These 2 amps were plugged into an expensive Monster surge protector along with other devices such as desktop, CD Players, Ipod Dock speakers...I was very disappointed and I determined that the problem had to be the poor QC of the Lepai 2020+ but when I disconnected the Lepai 2020+ power supply ( provided ) and I connected the Lepai 2020+ amps to a separated surge protection ( less expensive ACP products), miracle happened, no ground hum noise even when I put my ears closed to the speakers. I cannot be any happier right now with my Lepai 2020+ purchases.

 

I am not electrician so I cannot tell you why but there must be some interference among different devices that are hooked up to the same surge protector.

post #3 of 4

The PS provided does not contain an "earth" only pos/neg . Any earth therefore must come via the channel inputs. Its possible there are more than one "ground loop" -in other words -more than one earth return.If acdoans advice doesnt work check how many earths are provided by the preceding audio-equipment and if more than one -remove one earth connection at a time and try it.
 

post #4 of 4

Standard troubleshooting procedure:

a] Unplug any and all cables.

b] Connect power supply to the wall receptacle and speakers.

c] Turn-on.  Does it hum? does it whine? how about when you touch it?

d] If not, use a battery powered music source.

e] If still no hum, try a single AC powered music source. Connect it to the same AC outlet (no surge protectors  or power conditioners) and a plain-jane co-ax interconnect.

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