Earthing the n-Sub

Is the earth switch set to "internal"? If not, switch it to "internal".

Check that your n-Vi is set-up correctly with the subwoofer in the options menu.

Check the interconnect is the correct direction.
(try switching it around to see whether the hum goes away).

If you still have a hum then you should run an earth lead (any thin wire will do) from the external earth post back to the chassis of the n-Vi. If you do this then switch the earth switch to "external".

You might also wish to check that you have a good mains earth on both sockets.

Hi Richard,
I checked that it is set to internal right when I set it up

I am pretty sure the cable is the right way around. Unfortunately there is no indicator on the cable itself. But it was marked with one end for the sub. Then again, why would it hum. It's a coax cable. Directionality should not make a difference in hum?
I would switch it around but it's a 8m cable and I put it all in cable duct, so that would be a real pain *arg*

I thought about running a lead back to the n-Vi but again, that would be 8m....I don't want to

So connecting the external earth to the mains outlet is a no-go?

P.S.: How would I check to see if the mains earth on the sockets is good?

I don't know what cable you're using so unsure how it's constructed.

Do you have the hum if it's just the n-Sub and speakers connected to the n-Vi? (i.e. no TV or sat box/tuner)

Don't know about connecting the external earth to the mains earth. Might be fine but check with Naim or your dealer - I don't wish to be responsible for damaging your new n-Sub!

I usually like to to try and find out what is causing the hum in the first place. In most set-ups I only ever got hum through the n-Sub if I turned off the n-Vi before either muting or switching off the n-Sub.

Have you checked the earth potential on your sockets? There may be a big difference here if one socket has a loose earth terminal.

OK, obligatory health warning: If you don't know what you're doing or don't have the right equipment for this then DON'T TRY. Ask a qualified electrician to come over and check your circuits.

I actually have no TV or other display connected. The n-Vi is currently and for the time being will remain a 3.1 music setup for Music DVDs and Audio CDs. Mainly the latter.

I could try to disconnect the signal lead from the n-Vi and see if the hum is caused by the mains directly. Although it shouldn't.

I currently have no way of measuring the potential of the sockets. Broke my device a few weeks ago.

I'll disconnect the signal on the n-Vi side. If that doesn't help I will try to connect the power cord to the same socket as the n-Vi with an extension. If that doesn't help...well, I might try running an earthing cable through the room to check if earthing external n-Sub to chassis n-Vi would help.

P.S.: Is there some kind of standby mode on the n-Sub or will I always have to turn it off completely (something that isn't recommended for Naim's normal amps).

hmmmm. humm seems to increase if i leave the lfe cable connected at the sub but remove it from the n-Vi.

Looks like I will have to do some socket-checking tomorrow.

What about with nothing connected? Its not just the amp is it?

Is the hum defo coming out the speaker.

Yes, if you disconnect the i/c from the n-Vi you will certainly have hum though the n-Sub.

Check your sockets. Also check youve connected into the right socket on the n-Sub.

When not using the n-Sub I normally mute it, only switching off if I go away for a few days or more.

It's the subwoofer input/mono input. That should be the right one given that it actually gets the signal.

The hum is not from the speaker as such. It's from the amp or power-supply. Electronics.

Checked that the phase is correct on the power cord.

Will have to check whether it's better on a different socket tomorrow. I'll need to get my 50m extension cord first

It's not a really, really loud hum, but I am quite sensitive to that kind of background noise so it can't stay like that and be kept on. I would have to turn it off whenever I am not listening.

But let's see if I can get rid of it first.

By the way, did I mention that positioning the inputs underneath the n-Sub was a bad idea?