[korgypark] Re: korg pcif interface problem
- From: "Robert" <GnomeDePlume@xxxxxxxxxxxxx>
- To: <korgypark@xxxxxxxxxxxxx>
- Date: Sun, 27 Jan 2002 14:57:16 -0600
Proper grounding techniques are more or less still a 'Black Art,' though it
need not be that way. Many manufacturers of mid-to-low-end digital audio
gear still don't seem to have mastered proper signal grounding techniques,
either, and use a common ground plane on their circuit boards for both the
digital AND analog portions of the signal path. (Gawd!) To make things
worse, they usually don't provide enough bypass capacitance in the digital
parts of the circuitry to mitigate "thumping the rails" when a whole bunch
of gates decide to switch all at once! If you've got these problems at the
board level, just about the only choice you have is to migrate to higher-end
or better-designed equipment.
In case you've already got good equipment, and grounding probs are
elsewhere, please be aware that adjacent outlets in your "studio" (my study
is my studio, for example) may not share the same circuit breaker, and
consequently there may be a LOT of wire between apparently nearby outlets.
So, put all your computer and small-signal processing stuff on ONE power
strip (your limit is 15 amps or so), and your large-signal stuff (power
amps, et al) on a separate outlet. Then, wire the two outlet grounds
together (ONLY THE GROUNDS, PLEASE), using heavy-gauge wire. That way, you
won't have your equipment trying to push current through the connector
grounds, screwing with your signal quality.
Finally, if you're getting electrical noise from some source outside your
studio (like an air conditioner switching on and off), filter the power to
all your small-signal stuff (including computer(s)) through a ferroresonant
isolation transformer, or through a UPS that has a CLEAN SINE-WAVE output.
You need not filter the power to your Marshall stacks! :-) My ferroresonant
xfmr acts like a bandpass filter at 60 Hz (with something like 60 dB/octave
rolloff), and power-line transients don't have a snowball's chance in hell
(one 2 kV spike got flattened to about 1.5 V on the xfmr load side. Go
figure that in dB!) The cheaper square-wave UPS shit will KILL your audio
(and maybe your equipment, too)! Ferroresonant isolation transformers are
best for transient suppression, but hey, your audio is worth it, yes?
Something rated 1.5-2kVA should be plenty for a typical home studio.
-r
-----Original Message-----
From: Bill Gallagher WA3RA <ks3y@xxxxxxxxxxx>
To: korgypark@xxxxxxxxxxxxx <korgypark@xxxxxxxxxxxxx>
Date: Sunday, January 27, 2002 12:25 PM
Subject: [korgypark] Re: korg pcif interface problem
I have noticed the same thing...it is caused by a 'ground loop' between the
sound card and the and the synth. The PCIF cable ground and the audio ground
are not quite the same. I have 'fixed' the problem in my system by ensuring
that the PC and the synth are plugged into the same power stip, AND running
a separate ground wire between the synth and the soundcard.
Incidentally, I do not have the problem when I send the audio to a separate
mixer .
Cheers!
Bill G.
----- Original Message -----
From: "²»¥J" <victor.young@xxxxxxxxxxxxx>
To: <korgypark@xxxxxxxxxxxxx>
Sent: Saturday, January 26, 2002 23:39
Subject: [korgypark] korg pcif interface problem
> The problem I am having is quite strange. I connect korg x5d to computer
via pcif cable ,
> and also connect it to my sound card for monitoring.When computer send
MIDI message to
> korg x5d,I can hear little noise from monitor speaker.
>
> Does anybody have the same problem ?
>
>
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