Nord Electro 2 emitting EMF interference

[gordorama]

Hey there.
I have a Nord Electro 2 I use for organ work, but still use my Rhodes 54 for my electric piano.
Recently, I changed my set up and put the Nord on top of the Rhodes, only to get the worst EMF interference, most likely from the Nord's transformer being picked up by the Rhodes' Pickups.
Other keyboards don't have the same problem.
Anyone else have this issue?
Any suggestions? Can I shield the Nord's transformer, or is it the Rhodes that needs shielding?
Gordon

[Mr_-G-]

A standard way to avoid this is to use a Faraday cage. So you could try lining the rhodes cover interior with metal foil and connect that foil to the ground. How successful that will be i donot know.

[pterm]

gordorama,
I googled "shielding Rhodes piano" and came across a number of possible solutions. One of interest was the use of a single sheet of metal between the two keyboards.

At audio frequencies, the interaction between the devices is most often magnetic, so I looked up a magnetic shielding material company http://www.mushield.com/faq.shtml and they agree with Mr_-G- that a full enclosure is the best kind of shield. They also recognize that a single sheet of material provides some shielding. This might provide a simpler, but sufficient solution.

To confirm that the coupling is from the Nord's transformer try the following:

1. Verify it's not the cabling. Without moving the Nord, can you make the problem go away or diminish by changing the routing or positions of the Rhodes and Nord power and audio cables?
2. Does the problem get worse as the Nord gets closer to the Rhodes? Try tipping the Nord up or just lifting it away from the Rhodes.

If #1 has no effect, and #2 has a strong effect, this is likely a magnetic-field coupling problem and the Nord is the likely source.

The shielding material website suggests increasing the separation between the two devices is often the easiest solution. If your setup allows it, try increasing the space between the two boards.

Shielding the source provides another option. It might be easiest to affix some metal to the underside of the Nord to see if that lessens the problem.

The choice of metal is important, if a magnet won't stick to it, it makes a poor magnetic shield at low frequencies (below 10kHz).:

• Aluminum and copper provide poor shielding (but better than nothing)
• Steel is 10-100 times more effective
• There's a nickle alloy used for magnetic shielding called "mu metal" that is about 10X better than steel at these frequencies (but you're unlikely to have any about the house).

If you have a steel cookie sheet or pizza pan (check with a magnet), try placing that between the two boards, to see if helps. If it does help, then you can look at making the solution more elegant, like steel sheet inside the nord case near the transformer...

Let us know how this goes. It's an interesting problem! (at least to me)

[Mr_-G-]

A sheet of metal alone might not be enough. The faraday cage works because the charge inside a hollow conductor is 0. And it should be connected to the ground (the audio shield).

[OBDave]

Very common issue with Rhodes pianos. You basically have 54 single coil pickups in there. Grounded shielding helps. One solution is to use copper foil tape with conductive adhesive. Attach this tape to the (grounded) slidey things. But you need to make sure to line part of the tape with an insulating material so the foil does not ground out the windings where the wires are soldered.

This may not be enough to eliminate the hum from your E2, but it certainly helps with EMF noise in general.