Strange buzz... (Stage 73 MkI)

[levdave]

Hello ! I'm restoring my old Rhodes, and I can't find how to remove a big "buzz".
I've just uploaded a video to show the problem :
https://youtu.be/Rh8r7vChIGA

Would anybody have an idea ? 

TIA

  levdave.

[Ben Bove]

That buzz is not a typical native frequency for a Rhodes piano issue.  Especially that it's a stage, not a suitcase piano... a high pitch frequency buzz usually indicates something else going on.  It could either be something be close to the Rhodes (like a laptop resting on top, or being near a radio station, fluorescent lights or bad grounding with the amp). 

The most simple thing first - move the piano and have nothing near it.  Is the amplifier underneath the piano, or a nearby computer, WiFi internet, etc.? 

Second would be to check another way to hear the piano - a different amp, or plug into a recording device with headphones... try to eliminate other options first.  Then let us know.

[levdave]

Ok, thank you Ben Bove 
Tomorrow I'll make another recording without amp, directly in a recording device !
I'll tell you what will happen...!

[levdave]

Ok, so with your advices I tried to record the same thing directly into my digital sound recorder.
The buzz is quite different... seems more digital, and probably caused by the recorder itself...
But why does the buzz stop when I plug the pichup's wire to the ground ? While the buzz continues when I unplug the RCA !!

https://youtu.be/LJte2L5NGgA

Should I use Shielded Jacks ?

[Ben Bove]

The high-pitch buzz from your first video is gone.  So I am guessing the 1st video issue may have something to do with your amp, the location of the piano and the amp, maybe electricity ground in your house.  Just some guesses.

The second video, yes the digital noise is coming from your recorder - when you unplug the RCA cable, the same noise is present.  This means you hear the 2nd video buzz if the Rhodes is plugged in, or not plugged in.  So it can't be the Rhodes causing that buzz.

If you wanted to double check the Rhodes itself, my only suggestions would be to make sure the pickups are wired correctly according to the pickup schematic from the service manual, and to check all the ground points on the piano. 

[levdave]

Thanks again Ben, my buzz was caused by the amp, as you said  ...

Problem solved ! Now I've got a new one, but I'll create a new thread 

[Ben Bove]

Always great to hear a success story.