I purchased a Yamaha PSR 290 keyboard a while back-$180. I like it.
For the price I thought it was a bargain. The worst sounds on it sound
no worse than the best early eighties synth strings, and the best
voices sound good enough to use on a pro recording. Anyway, It
generates a bit of hum. For some reason this hum is absent when I'm
simply listening to the keyboard through headphones, but when I plug it
back into my external soundcard (through the headphone out--the only
out on the keyboard) the hum reapears. I'm using my computer both as
the midi controller and the DAW--perhaps there's a feedback loop of
some type there, or simply thourgh the AC connection, which is your
standard cheapo radioshack 3-12 volt multi adapter with no ground prong
on the transformer. I'm thinking about taking off the cover of the
keyboard, finding a screw, wrapping a bit of wire around it, and
splicing the other end into the ground lead of a three prong plug. The
plug would otherwise be unnattached. That is, no AC current will be
flowing throw it from the outlet.
Is this a good way to tackle this issue? Is it safe?

In article .com,
wrote:
I purchased a Yamaha PSR 290 keyboard a while back-$180. I like it.
For the price I thought it was a bargain. The worst sounds on it sound
no worse than the best early eighties synth strings, and the best
voices sound good enough to use on a pro recording. Anyway, It
generates a bit of hum. For some reason this hum is absent when I'm
simply listening to the keyboard through headphones, but when I plug it
back into my external soundcard (through the headphone out--the only
out on the keyboard) the hum reapears. I'm using my computer both as
the midi controller and the DAW--perhaps there's a feedback loop of
some type there, or simply thourgh the AC connection, which is your
standard cheapo radioshack 3-12 volt multi adapter with no ground prong
on the transformer. I'm thinking about taking off the cover of the
keyboard, finding a screw, wrapping a bit of wire around it, and
splicing the other end into the ground lead of a three prong plug. The
plug would otherwise be unnattached. That is, no AC current will be
flowing throw it from the outlet.
Is this a good way to tackle this issue? Is it safe?


No. Your problem is that you have too many ground lines, not too few.
Use a transformer (like a DI box or an isolation box).
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

After the keyboard and before the soundcard? How much does one of
those cost?

How can the issue be too many ground lines if the piece of equipment
that is producng the hum isn't grounded itself? I don't understand
that. Could you explain?

I purchased a Yamaha PSR 290 keyboard a while back-$180. I like it.
For the price I thought it was a bargain. The worst sounds on it sound
no worse than the best early eighties synth strings, and the best
voices sound good enough to use on a pro recording. Anyway, It
generates a bit of hum. For some reason this hum is absent when I'm
simply listening to the keyboard through headphones, but when I plug it
back into my external soundcard (through the headphone out--the only
out on the keyboard) the hum reapears. I'm using my computer both as
the midi controller and the DAW--perhaps there's a feedback loop of
some type there, or simply thourgh the AC connection, which is your
standard cheapo radioshack 3-12 volt multi adapter with no ground prong
on the transformer. I'm thinking about taking off the cover of the
keyboard, finding a screw, wrapping a bit of wire around it, and
splicing the other end into the ground lead of a three prong plug. The
plug would otherwise be unnattached. That is, no AC current will be
flowing throw it from the outlet.
Is this a good way to tackle this issue? Is it safe?


No. Your problem is that you have too many ground lines, not too few.
Use a transformer (like a DI box or an isolation box).
--scott


After the keyboard and before the soundcard? How much does one of
those cost?

How can the issue be too many ground lines if the piece of equipment
that is producng the hum isn't grounded itself? I don't understand
that. Could you explain?

Hi,

I just bought one of these on closeout just to muck around on but it won't be
here for a couple of days so I don't have the answer to your question. I'll be
interested in any replies in case I run into that problem. In the meantime I
wouldn't mess around trying to ground it yourself as you have described.
There should be an external solution, as the other poster mentioned but I could
use a little more explanation too.

Meanwhile you might try posting this question to rec.music.makers.synth

Cheers