PC for Brsyton 4B SST

Freaky, any wire will do...lamp cord...some old speaker wire...anything insulated where you touch it and with bare ends. The ground screw will be obvious if you look on the back of the receiver or amp. Plus, you don't need a ground screw to do the test...just any bare metal or screw that's part of or attached to the chassis.

I asked about two channel vs. multi-channel because I wanted to know whether the idea of a different preamp or receiver was the right choice. So, you're using the Bryston for amplification of front left and right channels? Did you buy the Bryston from a dealer? If so, perhaps they can loan you a Bryston SP 1.7 multi channel processor to test. Otherwise, a different multi channel receiver. It sure seems to me the NAD is the culprit. Again, the hiss is common.

Unfortunately I bought the amp from a fellow Audiogoner.

Yes the amp is for amplifying the Lt and Rt channels. It might take some doing in obtaining a loaner piece of any kind, but I'll try nonetheless.

What would it mean if I try the wire test and the buzzing goes away or stays the same.

If the buzzing goes away, connect it with a couple pieces of tape. It made the buzz go away, right? So, it means it worked!

If the buzz is still there, then you're back to the beginning. But I seriously doubt any power conditioner is going to make it go away. Try calling NAD and asking them if your model receiver is grounded or not. If it's not grounded and the Bryston is, then that might explain the buzz. It'd also explain why the wire might work, because by connecting the NAD chassis to the Bryston chasssis, you're in effect grounding the NAD to the Bryston. At least this is what I've been told by others wiser than me.

When doing the wire test should the wire be at least a certain gauge.

Freakygreek - Tvad's suggestion is a good one, assuming the "buzz" you are hearing is ground hum. What often happens is that the ground potential between two components is different, causing a ground loop.

What you are trying to do by connecting a wire between the two chassis' is equalize the potential, thus minimizing the loop. You will need to make sure that you are connecting the wire to a grounded point on the chassis of each component. Chassis screws are usually good for this, and there's an easy way to make sure the screw is grounded if you have a meter.

If you have access to an ohmmeter or multimeter, disconnect the component from power and the rest of your gear. Set the meter to read in ohms, then touch one lead to the screw you want to use as a connection point for the wire, and touch the other lead to the outer sleeve of an RCA jack on the back of the component. If the meter zeros out, the screw is grounded. If it doesn't, look for another screw until you've found one that does. The screw is grounded to the chassis, and you can use it to attach the wire.

Your wire should be long enough to connect the grounded points on the two chassis' of course. Since you are trying to equalize ground by giving it a better path, you want the wire to be at least the same gauge as the ground wire in the thickest power cord you are using. So, if your Bryston amp's power cord is 14ga, you want the wire to be at least 14ga. 12ga would be better, but no need to get ridiculously large. Make sure it's insulated wire - bare wire could touch something else and create a bad ground.

Connect the wires as Tvad suggests, and see if the buzz goes away. If it does, you can make it fancy by getting some lugs so that you can more easily connect the components with the ground wire.

If it doesn't go away, and you don't have any other components connected, your buzz is probably not from a ground loop. It's probably from something like flourescent lights or an electric motor on the same electrical circuit. If that's the case, you will have no choice but to move the audio gear onto another circuit if you want to get rid of the noise.