Speaker and headphone hum

Kwan that sounds like some sort of earth loop or perhaps a source is earthing through the signal connection to the Supernait.  What happens if you disconnect the Pioneer from the Supernait?

p.s. The Supernait needs to be earthed at the mains.  Without an earth it's potentially unsafe should something catastrophic happen.

Hi Richard, I did disconnect the Pioneer and change the power between them, but when I plug in directly into wall socket, the humming sound come back.

I know it is unsafe, so I am extra caution at the moment, mostly switch it off after play.

Thanks

Kwan, have you had the mains and socket checked?  Is it all OK? 

Kwan, as Richard says check your socket. Polarity checkers are an inexpensive ($5-10) common device you plug directly into an individual socket that will diagnose, through a series of LED lights, the status of the connection. If a fault is indicated call a pro. That's what I'd do.

Kwan, I believe you are not in the UK? The Powerline is a UK plug, maybe it is not compatible with the mains/earthing arrangement in your location? You could check this by using a regular IEC lead into a normal mains socket. 

I will check the main socket again, however, the same socket was working fine when I connected to audiolab amp. 

Chrissu, you are right, I live in Shanghai, I did tried other power cable connect to wall socket, but it got the same result as powerline lite.

I used a coventer with earth (three pin) to wall socket for powerline.

Thanks

Kwan

Kwan posted:

I will check the main socket again, however, the same socket was working fine when I connected to audiolab amp. 

Hi Kwan,  a big clue is that it was not a problem with the Audiolab amp;  what model (number) was it ???   as some Audiolab units have L&N only & do not have an earth connection.  Incidentally the Pioneer N-70AE also has no earth connection.   It could be the SN is looking for a signal ground (earth) & is getting that on the neutral return line & that is carrying an AC element & thats causing the noise. 

If you do decide the problem is with the wall socket (house) earth it might be better to have that checked & repaired professionally.

That’s what I was thinking too, Mike. If that’s the case, though, us the house earth faulty, though, or is it like that by design?!

Hi Mike, the audiolab I have was M-one, it has earth connection, I did connected to the pioneer for few weeks before I sold it. you are right, N-70AE has no earth connection.

I have ordered an MK socket, once I get it, will arrange electrician to change it.

Thanks

Kwan

Hey Kwan,  the Audiolab M-ONE does not have an earth connection - see the picture, it has only two pins in the power receptacle.

When the electrician comes to change the power socket please be sure to tell him that you suspect something is wrong & to check, not just to change it.

Sorry Mike, I must have mix up, I was using a power cable with earth pin from day one, which was given to me by a dealer.

Surely, will the wall socket before replacement.

Thanks again, this forum have been helpful to me.

Kwan