Clavinet on top of wurly makes huge buzz

[dantone]

Hello.

My clav is making huge buzz from the amp when I put it on top of an wurly. When I pick it up, the buzz goes away immediately. Is it because the single coil pickup of clav is picking up the power transformer of the wurly or something like that?  I live in Finland so I have 230v on the wurly.

If this is the case, how can anybody keep clav on top of wurly?

Reg. Dan

[OZDOC]

Yes, you're correct.

You can experiment with how far above the Wurli the Clav needs to be for the buzz to be acceptable.
Then buy a stand that holds it above the Clav at that distance.
You can make sure the Wurli is disconnected from power when you play the Clav.

You can also experiment with an earthed metal plate between the two, or an earthed box around the transformer in the Wurli.
(Remember, in the latter case, you're dealing with mains voltage.)
It may also be possible to have the Wurli transformer changed for a toroid style one that radiates less magnetic field.

Another solution that some use is to place the Clav above another electrically passive instrument such as a Stage Rhodes.

[dantone]

Thank you for your reply. 

[Electrickey]

I would try shielding the Clav and not change parts in the Wurli to retain its tone.

What year is your Clav? Is it a D6?

By around 1977, Hohner released a model that was shielded to address the noise problem.

So let's say the Clav is the issue not the Wurli.

But there are work arounds by shielding the Clav's amp.

This does not involve using "hiss" caps which ruin the classic Clav tone.

A copper box is made and connected to ground.

Shield the electronics or get a keyboard stand to lift the Clav further away from the Wurli.

May not be ideal but back when these were made no one thought about players stacking them one on top of the other.

[Jenzz]

Hi .-)

Shielding the Clavinets PCB will not solve the problem. The main issue is that the 2 clavinet pickups are sitting above the Wulys transformer when in place. The magnetic field of the transformer will be picked up by the PUs, causing hum. A late D6 has a metal shield plate at the bottom where the pickups are, but in this case that will not help that much.

Try to experiment with different positions or distance of the clavinet on top. In the end, the only way to get totally rid of hum will be to place the transformer outside of the piano...

Jenzz