60-cycle hum...Best way to ground in this situation?

[sweetbeats]

I got my M-520 all hooked up last night and there is a definite 60-cycle hum. Not crazy-like, but it's for sure there and not too good sounding. Could be a lot of things but I'm thinking the best place to start would be to ground the chassis of the mixer power supply.

Here is the power setup at present:

1. The M-520 is plugged into a Furman PL-8 power conditioner via its 2-prong plug.
2. The PL-8 is connected to a grounded receptacle through it's 3-prong cord, then to one receptacle of a 3-way power splitter and then to a heavy-duty extension cord to the wall-receptacle.
3. The e-panel is for sure grounded to earth in one location, and close-by at that.

So the question is, what is the best way to continue the ground present at the receptacle of the PL-8 to the chassis ground lug on the back of the M-520 power supply?

 

[A Reel Person]

Beatz!

On the PS-520 there is a screw terminal lug for earth ground. You need to attach a length of wire to this lug, & route it down to the "ground" receptacle on the AC power (wall) connector, by using a simple banana plug that fits the "3rd" hole in the socket.

[Ignorance<<] Isn't that detailed in the manual?

 

[sweetbeats]

COOOOOL!

I don't know if that is in the manual or not...I have read it cover to cover at least once and read and read several sections in detail, but its probably in there.

I bet my local electronics shop has one of those things...

So I'd need to carry the wire back to the wall receptacle, or can I just go up to the PL-8?

 

[A Reel Person]

Yeah.

I think either is fine. The main emphasis is on differentiating hooking up to the ground receptacle vs. either of the others (hot & neutral). A no-brainer, maybe???

I like calling you Beatz! I'd not want to have to call you Sparky! ...(or Smokey!),... but a'ter that 58 deal I dunno! >>[J/K]<<

D'oh!

 

[sweetbeats]

Safety first...

Plus, leave it to me to not wear my glasses and try to shove the thing in the wrong spot when I can't really see well...like for instance when plugging an amp card into the extender card on a...uh...Tascam...58...pffft!

 

[A Reel Person]

Gee, yeah,... I'd forgotten all about that one!

Heh, heh!

 

[analogkid]

mom always said to stay grounded...

That should handle it!

 

[sweetbeats]

This is wierd...

There really wasn't much improvement when I grounded the power supply...I took some 14awg solid core copper wire, found a toast 3-prong extension cord, cut open the remaining molded end, tore out the ground prong and after about 15 minutes of work with a dremel and a soldering iron I had a nice ground wire (see below).

Anyway, the lights in the control room are making a lot of noise, so during tracking or critical listening I'll just shut them off, and I'm sure that all my crazy wiring is not helping...the control room is so tiny and I have so much gear in there, and a bundle of unbalanced snakes going hither and thither. Patchbays aren't grounded...don't know what else would be easy to try...not too concerned at the moment even though I have a tracking session tonight, except for one strange thing...

The scenario is two mics, one a small-diaphragm phantom powered condenser (Shure SM94), the other a small diaphragm dynamic (SM57). When I monitor the inputs directly at the output of the DAW, the condenser is quiet as a tomb, but the dynamic has quite a hum. I tried a different channel on the board, and different cable run, same thing. If anything was going to hum my intuition says it'd be the condenser...