LED Back Light causing line noise

guyb wrote:
MPC500 -> unbalanced jack -> EMU 1616 -> balanced speaker cable -> KRK RP5

(The preamp is very noisy at high gain also but what do you really expect!)

Why are you not using balanced cables with the 500?
If the pre is noisy it not setup up properly.

Sovereign wrote:

guyb wrote:
MPC500 -> unbalanced jack -> EMU 1616 -> balanced speaker cable -> KRK RP5

(The preamp is very noisy at high gain also but what do you really expect!)

Why are you not using balanced cables with the 500?
If the pre is noisy it not setup up properly.

The 500 is really noisy itself! There is a high constant tone and a lower humm.

Because I haven't gotten around to buying balanced cables yet! I do intend to, but since I use it more as a sketchpad than a workstation the general noise floor isn't a huge issue. Thinking about it, the USB whine is present even if the output cables aren't plugged in, so it is not unbalanced cables that are the problem. The pre-amp is just not a great pre-amp, it works fine, but at the high end of the gain range is noisy.

Ok I give up, I won't keep wasting time on the subject since people have no clue.

All I know is it stops when I cut the back light off.

I recorded the noise here... This is me turning the Backlight On Off On Off On Off On... listen to the noise go on & off... I know it's staticy but I had turned the vol all the way up and then I normalized the file a lil so you can hear it better...But peep the shrill

http://soundclick.com/share?songid=7026578

Sovereign wrote:Ok I give up, I won't keep wasting time on the subject since people have no clue.

Then try to sample "nothing" and then normalize. Then you will hear the sound we all are talking about. Get the clue son.

Here's the same audio of the Backlight being turned On Off On Off On Off On <<in that order) but I ran it thru a noise reduction to get rid of all the other noise and single out the shrill tone.

http://soundclick.com/share?songid=7028665 <<this def proves the backlights causing or playing a role in the culprit noise.

Looks like were running out of ideas on a resolve for this but I'm posting this just in case some one hits a stroke of brilliance (couuughguyb) or luck in coming up with a fix.

I've had that noise in the past when connecting things to computers with cheap audio devices or sound cards and/or cheap cabling.

The problem is somewhere in your system, not the MPC. Get better (correct!) cables and use a decent audio interface. Is that doesn't work you're looking at electrical issues where mixers/amps/computers are on the same circuit as each other and not playing well.

Like I said, read about ground loops:

http://www.audioholics.com/tweaks/conne ... m-and-buzz

Thanks bedouin

I got decent cables, brand name "Hosa"... decent interface & a decent 24 bit soundcard

the thing I'm not understanding is how when I cut off the backlight does the noise stop?

Appreciate the link to ground loop info... I read the whole thing.

if you have to really gain up to hear it then its hardly worth worrying about it, many of my machines make noises you can only hear if you gain up like that. Still if you can eliminate that by turning off the backlight, then do that before you record. But its way below the noise floor so dont worry about it really

phono wrote:if you have to really gain up to hear it then its hardly worth worrying about it, many of my machines make noises you can only hear if you gain up like that. Still if you can eliminate that by turning off the backlight, then do that before you record. But its way below the noise floor so dont worry about it really

I kind of agree, just sayin I can hear it without the gain turned up... aint that big of deal to just turn off the backlight tho... I'm cool with that... I'm makin love wit my 500 right now

This sound could be real hardcore soundscape.
http://rapidshare.com/files/161617345/M ... e.mp3.html

I'm having these noise issues too. I can hear them with just headphones on. I can hear it with plugin powered and battery powered. I noticed the noise when I powered up my mpc the very first time so I really dont care about it anymore. Ive noticed that the noise get stronger and more noticeable when Im saving, loading or changing modes etc. I think its just the fact that the mpc's audio signal routes aren't well protected and they get interfered by the other electrical components in mpc or something like that.

Its not really big of a problem to me, but Im a bit disappointed of the fact that mpc500 isnt really usable as a field recorder. The noise of mpc really is annoying when youre trying to record ambience with a mic in it.. I try to think positively, its just part of mpc's charasteristics

Turning off the backlight does reduce the noise, which I am pleased about. I have also noticed that if I turn the volume knob about, the remaining noise rises and falls. At the moment I have it set to the 3 o'clock position because it seems quieter set there.