When I got my new MkIII Disklavier last year I
noticed the same thing. I have a very audible 60 Hz hum coming out my DKV
speakers -- not outrageous, but definitely audible. When I connected the
aux outputs to an amplifier it WAS outrageous. The aux outputs are quite
low level -- not at all full line-level signals. Thus a modest amount of
60 Hz hum on these lines will be amplified disproportionately. I spoke to
Bill Brandom at Yamaha -- he was familiar with the problem and recommended
the use of a mixer/preamp with the aux outputs. I picked up such a unit at
my local Guitar Center outlet, and it brought the hum down to a tolerable
level. I still hear the hum very clearly, but frankly most ;casual
listeners don't notice it.
My conclusion is that while Yamaha did a fantastic
engineering job on the basic DKV instrument, the electronics design did not
receive the same degree of attention. Yamaha has in their corporation a
world class audio electronics arm, and the design techniques for minimizing and
eliminating line frequency hum are well understood. It is beyond my
understanding why they did not apply some of this knowledge to the DKV
electronics design. Proper grounding, filtering and shielding
throughout could eliminate this problem, but it would take an electronics
redesign to accomplish it.
Jerry Dutcher
----- Original Message -----
From: J DSent: Tuesday, November 23, 2004 5:05 PMSubject: RE: [disklavier] hum from amplifier>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 > > >I have a similar problem with my DC7A. It is more noticeable when I have recorded from the auxiliary outputs. I will be interested in knowing what you guys suggest.
Thanks,
John W
>I have a new DC1A with an intermittent problem: There is
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