MPC 3000 -- High pitch whine when sampling

I've read some threads on this, but Im not sure which category my problem falls into. My MPC 3000 produces a high pitched whine out of both the outputs and headphone jacks when im in 'sample new sound' mode.

The whine gets recorded. The higher the record in volume, the higher the whine.

Ive tried turning off the display completely.

I've also tried with and without any SCSI connections

In general, the samples have been recorded into my computer. Then, using an Apogee Duet 2, I send them out the 2 main outputs, into the 2 analog ins on the MPC.

Any other ideas on what to investigate?

dtirer wrote:Any other ideas on what to investigate?

Investigate whether the noise is coming from the USB interface to MPC connection?

Does the noise go away when you unplug the connection to the MPC from the Apogee interface?

Does the noise happen with other types of devices connected to the inputs, like keyboard/drum machine/mixer/hifi/etc.?

OK here's what I've found. It seems to be the interface interacting with the MPC.

If I sample a drum machine directly into the MPC (no interface), everything sounds fine. If I turn up the record level, you get obvious raise in noise floor.

If I plug in the interface to my macbook, and either start running inputs through the interface, into the the computer, and back out the interface into the MPC, I get a get some high pitched whine. If I keep the MPC record level very low, it can be very unnoticeable. If I turn up the record level, and put it on medium or high, not only does the noise floor rise, but i get all sorts of digital grably sound, and the whine increases as well.

Same situation applies when I'm playing pre-recorded sounds out of my computer, through the interface, into the MPC.

However, when the MPC is not involved, and I'm recording something using the Apogee, there are no issues.

any thoughts?

SimonInAustralia wrote:

dtirer wrote:Any other ideas on what to investigate?

Investigate whether the noise is coming from the USB interface to MPC connection?

Does the noise go away when you unplug the connection to the MPC from the Apogee interface?

Does the noise happen with other types of devices connected to the inputs, like keyboard/drum machine/mixer/hifi/etc.?

dtirer wrote:any thoughts?

...common problem when connecting via USB interfaces?

Possibly a ground loop or some other sort of electrical leakage into the signal lines from the USB connection.

No idea what the solution is, but I have seen it a number of times before when connecting USB interfaces to other things.

Maybe some sort of electrical isolating box, or mixer, or other device, in between the USB interface and the MPC might help?

Other possibilities...find another way to get the sounds into the MPC, either direct from the source into the MPC, through a different interface that doesn't have the same problems, through an SPDIF digital output on the a computer interface to the SPDIF digital input on the MPC, via file conversion/transfer from the computer to the MPC via some sort of removable storage, etc.?

I have a duet 2 and noticed a hi pitched whine when tracking out of the duet into an API mic pre and then back in. I talked to apogee about it, they suggested to try using the power cable that comes with the duet2. I couldn't find mine so I never tried it.
Other than that they didn't really have much to say.

Ive used the duet2 to sample into my 3k but dont remeber the whine.. but i havent used it recently. the duet 2 should sound stellar in terms of D/A to get to your mpcs analog inputs.

Oh i see. i'll have to talk to Apogee and see what they say. I wasn't aware this was a common problem

SimonInAustralia wrote:

dtirer wrote:any thoughts?

...common problem when connecting via USB interfaces?

Possibly a ground loop or some other sort of electrical leakage into the signal lines from the USB connection.

No idea what the solution is, but I have seen it a number of times before when connecting USB interfaces to other things.

Maybe some sort of electrical isolating box, or mixer, or other device, in between the USB interface and the MPC might help?

Other possibilities...find another way to get the sounds into the MPC, either direct from the source into the MPC, through a different interface that doesn't have the same problems, through an SPDIF digital output on the a computer interface to the SPDIF digital input on the MPC, via file conversion/transfer from the computer to the MPC via some sort of removable storage, etc.?

do you record with a laptop or a desktop computer? if lapotop, have you tried unplugging its powersuply?

Yep have tried that. I need to get a ground lift on the mpc and see if that helps

aaonli wrote:do you record with a laptop or a desktop computer? if lapotop, have you tried unplugging its powersuply?

So I emailed Apogee and he said the outputs on the apogee are balanced, so I might want to try using a balanced cable...How would this work in conjunction with the Apogee? Would I need TRS to TS?

dtirer wrote:So I emailed Apogee and he said the outputs on the apogee are balanced, so I might want to try using a balanced cable...How would this work in conjunction with the Apogee? Would I need TRS to TS?

The MPC3000 has balanced inputs, so you would use TRS to TRS cables to get a balanced signal from the Apogee into the MPC.

I'm not convinced it will make a difference to your problems, as balanced audio circuits/cables are designed to reject interference picked up by the cable, mostly over long cable runs, and usually don't make any difference on shorter cable runs...

...but as the ground path, when using a TS/unbalanced plug in the MPC3000 input, through the cable/plug from the Apogee to the MPC, is connected to the cold side of the balanced audio input of the MPC, as well as the ground connection of the balanced audio input of the MPC, at the same time, maybe a noisy USB ground from the audio interface is getting in through the audio cable ground connection to the cold side of the audio circuit on the balanced MPC input...

...so I think it is worth a try, with a TRS to TRS (balanced) cable to see if it is any betterer.

I have the same issue at times with an RME PCIe card attached to a Multiface II. The suggestion there was also to power the interface with a dedicated power pack. Using one the whole thing grounded properly and the issue vanished.

Well i guess a big issue is that my apartment is so poorly grounded. But then again, I've used the MPC in other places with the same problem.

The guys at apogee said to trying using balanced connections from the Apogee to the MPC in, so I have to try that

Metatron72 wrote:I have the same issue at times with an RME PCIe card attached to a Multiface II. The suggestion there was also to power the interface with a dedicated power pack. Using one the whole thing grounded properly and the issue vanished.

dtirer wrote:Well i guess a big issue is that my apartment is so poorly grounded. But then again, I've used the MPC in other places with the same problem.

No, it is a common problem with connecting other gear to a USB audio interface, not specific to your apartment, or to Apogee, or that particular interface model.

one more thing to try out... try having the computer/interface plugged into a different power circuit from the mpc... run a good extension cable to another room or plug if needed... see if you use another plug that is on a different breaker if maybe that stops the issue. I have a POS laptop that can sometimes do that but it most often happens when running a cheapo interface from the usb to a PA system...

Sorry to resurrect an old thread, but this is in a fairly similar vein, so I figured I'd add on rather than start a new thread.

So i'm aware that there can be some noise from the headphone jack on the 3K, which is fine, I rarely use it.

And I know that a USB interface going into the analog ins can cause hum/whine too.

Recently I got an external CF reader. So I've been transferring samples on to the 3K via that. I just noticed that in any 'dead air' in a sample, there's this digital noise / whine happening out of all ouptuts (main, headphones, individual). So if I have a snare sample, and there's a long decay on it, I hear this high pitch noise as the sample starts to decay. Interestingly, if I play the sample at different velocities, the high pitch noise seems to change. If I play at a fixed velocity, it's always the same.

I also tried cropping the sample so that only the end of the decay is playing, and i just hear the high pitch noise in that situation too.

It's not the samples themselves though. If I play them on my computer, they're fine.

other things I tried that didn't seem to help:

1) sampling 'dead air' through the MPC analog inputs. When I store the sample and play it back on the pads, the high pitch noises happen.

2) disconnected the CF reader

3) tightened the screws on the bottom of the MPC

5) turned off the backlight.

6) tried different power outlets.

Any suggestions as to what this could be?

I can also record an example if that'll help