Disklavier

Hello J. Young

 Is it a HUM or is it an occasional rattle-a vibrating sound that
maybe mistaken to be a HUM-.? When you hear the HUM which is comming
from the AMP unit underneath the piano, simply go underneath and touch
the mesh that covers the amp, see if you can make it change. Reason?
These units have Hi frequency shunts-shunt being used loosely to make
a point- that are like litlle donuts in which the wires are wrapped
and cancels RF. Now, at times when the distance between the mesh and
the shunts are just far enough but close enough to move away and come
close just as the field is changing polarities, you will hear a rattle
type hum from the AMP but not from the speakers. Same principle as a
voice coil just not musical!!!

I hope this helps!!  

DKV1AB
--- In disklavier@yahoogroups.com, "FrJJY" <frjjy@y...> wrote:
> 
> I have a new DC1A with an intermittent problem:  There is 
> occasionally a hum that comes from the amplifier - perhaps the power 
> supply.  The noise does not come through the speakers but comes 
> directly from the amplifier box.  Has anyone else had this problem?  
> Unfortunately, the problem disappeared when my tech arrived, but of 
> course, reappeared after he left.  Any solutions?
> 
> Thanks.
> 
> J. Young