m-audio fast track mkII high-pitched noise

ferchis · Post by **ferchis** » Fri Apr 27, 2012 2:14 pm

Hi to everyone!

I'm getting a bit annoyed by the constant presence of a low high-piched noise every time I plug an instrument to my M-audio fast track mkII. every time I playback audio or use Sonar 8.3.1 to record, I hear this noise which would be bearable if only it DIDN'T get INTO the recordings!

I'm running Sonar in Windows 7 ultimate 64 bits, and I should stress that this DOESN'T happen with an HP notebook running the same Sonar but under Win 7 32 BITS. I kwow this may sound strange, and at first I thought it was related to the RCA outputs going to the monitors/speakers, but after testing all the different USB ports and getting a reinforced/isolated RCA cable, the noise is still there every time I try to "listen" to the instruments coming into the INPUTS in the Fast Track.

Any ideas? what should I do to stop this?

computer specs:

AMD Phenom x6
8gb ram
HD 500gb
Asus mobo

I'm desperate!! can anyone help!!??

ferchis · Post by **ferchis** » Sun Apr 29, 2012 1:29 am

nothing?

quick update, I've just realised there's sth going on with the electricity, since the noise is there EVERY TIME I have the Kronos plugged in!! but if I unplug it, then it goes away.

is that a ground loop?

xmlguy · Post by **xmlguy** » Sun Apr 29, 2012 2:30 am

ferchis wrote:nothing?

quick update, I've just realised there's sth going on with the electricity, since the noise is there EVERY TIME I have the Kronos plugged in!! but if I unplug it, then it goes away.

is that a ground loop?

Yes, it could be a ground loop, ground noise, or a floating ground. These problems can be caused by cheap computer/laptop powersupplies that have an incorrect reference ground voltage, insufficient filtering to prevent power line noise from being sent to the ground over the USB cable, or a USB shield that's not connected to ground. If you have a cheap powersupply, then usually it's best to replace it, since it will probably last longer, run cooler, use less electricity, and be quieter, in addition to havng better voltage regulation and filtering. Someone who knows electronics could use an oscilloscope to diagnose the problem with greater precision, but failing that, replacing a power supply isn't such a bad solution. Sometimes it can be the voltage regulation on the motherboard, however, and that's not so easy to replace.

Another common solution is to isolate the ground between the keyboard and the audio interface by using a direct inject (DI) box that has a ground lift feature. You would use the balanced output(s) from the Kronos into the DI box, then balanced out from the DI box to the audio IO box. That will only fix a ground loop between the keyboard and the audio box. It won't fix any ground noise that's being transmitted over USB from the computer to the audio box.

It could also be a problem with the powersupply ground on the Kronos, but the computer powersupply is a higher probability. Be sure that the Kronos and the computer are on the same electrical circuit from a single power outlet. Plugging into different circuits can cause a ground loop differential.

ferchis · Post by **ferchis** » Sun Apr 29, 2012 5:58 am

well... I've got grand news!!

I've fixed it!!! I really can't believe I did it, but it actually worked! it was extremely simple: just an adapter!! yes!! actually, 2 adapters, one after the other, and the noise is totally gone, I mean COMPLETELY gone!!!

thanks xmlguy for the comment. so apparently there WAS some sort of electrical interference or loop, but it just went away by putting to otherwise useless adapters in the socket where I plug the Kronos.

amazing... if there's any other news, I'll let you know.

cheers!

ferchis · Post by **ferchis** » Sun Apr 29, 2012 5:59 am

putting to otherwise useless

sorry, I meant TWO otherwise useless...

xmlguy · Post by **xmlguy** » Sun Apr 29, 2012 6:18 am

Glad you found a solution. What kind of adapter? A 3 prong to 2 prong AC power plug adapter? That would lift the A/C ground, although it intoduces a potential shock hazard if a 110/220 hot wire ever shorts to the case, because the lack of a ground will cause the short to flow through the body of anyone who touches the case. This is not common, but it does happen. I have personally been shocked by gear due to an AC adapter that lifts the ground. It happened during the setup for a live gig when I was the soundman and the keyboardist had an old amp with a short to the case. he used the adapter to solve a ground loop without telling me, and he did not get shocked because he was never grounded when touching the amp, yet I got a shocked when I was hooking a grounded mic cable to the amps line output.

But if you are referring to an audio adapter, then that will not create a shock hazard because only the audio signal ground is lifted, not the A/C power ground.

gondar5678 · Post by **gondar5678** » Mon Aug 31, 2015 9:13 am

the instruments coming into the INPUTS in the Fast Track.
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