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In my home studio the Korg Kronos L/R outputs are plugged in a Focusrite Scarlett 18i20 and to the computer. The Kronos is generating lots of noisy.

The problem doesn't come from the cables or the speakers They work fine in other situations.

Strange enough, this happens even if the Kronos is turned off and unplugged from the outlet. When I unplug the cables out of the Kronos L/R audio outputs the noise stops and it starts again as soon as I plug them back in.

Has anyone experienced that kind of problem?

Without having any problems about noise, I have chosen to use the digital output of the Kronos. I have the same Scarlett 18-20 V3

What sort of noise? Hum, hiss, or noise varying in character over time?

Is the Kronos connected to anything else, e.g. via MIDI or USB?

It could be that the computer to which the Focusrite is connected to has a noisy ground. This is not unusual, and it can cause issues. Even the Kronos' own USB connectors are noisy against the analogue ground of the Kronos' audio connections. Routing the computer's power supply lead close to the Kronos' own power lead may help, as will using a common mains supply outlet.

Are there any strong sources of electromagnetic field nearby e.g. motors on washing machine, aircon, machinery, induction hob cooker, which could induce currents in the audio leads? The Kronos will also be acting as an antenna.

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Marmus wrote:Strange enough, this happens even if the Kronos is turned off and unplugged from the outlet. When I unplug the cables out of the Kronos L/R audio outputs the noise stops and it starts again as soon as I plug them back in.

This is probably a ground loop, and these fuckers can be tricky. You can try connecting different elements to different electrical plugs.

I had one when I had my MBP using the computer monitor for power delivery for the laptop, with the Kronos thorugh a Apollo Twin X via Thunderbolt, it solved itself simply using the original Apple power brick even!. Not to say this is your case, but it's a testimony of how devilish this can get.

@fomalhaut
Thanks for the reply. It seems to me to be a ground loop as well but I was wondering if it was caused by the Kronos. I didn't have time to investigate further on but I'll keep you informed when I have more information.

@voip

What sort of noise? Hum, hiss, or noise varying in character over time?

Thanks for answering, it sounds like static electricity. The Kronos is connected via USB to a HUB which is connected to the MAC.

No strong source of electromagnetic field near by.

You got my attention when you pointed out the USB port of the Kronos. When I unplug it there is a big drop of the noise volume. But still I can hear it. This happens even when the Kronos is turned off but it stops if I unplug the Kronos from the wall outlet.

No noise at all thru the headphones. Everything sounds great.

How can I fix this? This seems to be a problem in the Kronos itself. I have no other keyboards that generates noise in the same environnement.

Your problem might be linked to the electrical outlets where you plug your stuff. Try to plug all your low consumption gear such as synths etc at the same AC outlet, using a power bar or, much better, an UPS.

Other similar problems and ground loops can be linked from badly installed AC outlets (incorrect ground, hot/neutral reversal, etc.). If in doubt about this, you can find cheap AC outlet testers at any hardware store. Oh and... did I mention an UPS is very good to protect your Kronos ?

Not only do I have a UPS, I also have a Furman AC215A power conditioner. It's there because the surge protectors in a typical UPS aren't as robust, and the ones in those little power strip cords could just as well not be there.

Of course, depending on how enthusiastic Zeus is when he's throwing down lightning bolts, no surge protector is completely invincible. That said, I live in the country north of Atlanta and power can be a bit flaky, hence the additional protection.

So, a UPS to keep it powered up if there's a momentary blackout, and a reasonably robust surge protector to keep it from getting fried if Bad Things happen.

Marmus wrote:@fomalhaut
Thanks for the reply. It seems to me to be a ground loop as well but I was wondering if it was caused by the Kronos. I didn't have time to investigate further on but I'll keep you informed when I have more information.

In my case, I swear I could *hear* the noise changing to a modem-like noise pattern just simply using the mouse in the computer to scroll on a long Safari Window.

If a ground loop is present, the culprit can be anything thas is electrically connected in your set up (and not only via audio): the Kronos, the audio interface, the speaker monitors, the computer, the display monitor, the webcam, the printer, an electrical extension cable... Balanced connections are supposed to help here, but mainly you are looking at a lengthy trial and error scenario. Try to find the minimal setup that doesn't make noise and start adding devices one by one. Good luck!

Also, remember you can use digital S/PDIF (or even USB audio) with the Kronos, you will certainly still hear the noise but it will surely not be recorded.

If the noise cannot be heard through the headphones, then it suggests that, at least internally, the Kronos is probably OK.

Try connecting the headphones to each of the Kronos main L and R outputs in turn, with all other connections removed (apart from mains power) to see if the noise is present there, just to rule out the Kronos' L and R output stages. It won't do any harm to the Kronos. When listened through these outputs, sounds played on the keyboard will sound somewhat different, because they will be in mono, and left and right ears will be out of phase, because you will effectively be hearing each side of the balanced outputs. The important thing is to listen for the presence/absence of the noise.

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Make sure ALL of your gear is on the same physical wall outlet. The ground potential has to be the same. Even if different wall outlets are on the same circuit, there could be a difference of ground potential.

Marmus wrote:@fomalhaut
Thanks for the reply. It seems to me to be a ground loop as well but I was wondering if it was caused by the Kronos. I didn't have time to investigate further on but I'll keep you informed when I have more information.

Are you using balanced (TRS) cables?

Marmus wrote:In my home studio the Korg Kronos L/R outputs are plugged in a Focusrite Scarlett 18i20 and to the computer. The Kronos is generating lots of noisy.

The problem doesn't come from the cables or the speakers They work fine in other situations.

Strange enough, this happens even if the Kronos is turned off and unplugged from the outlet. When I unplug the cables out of the Kronos L/R audio outputs the noise stops and it starts again as soon as I plug them back in.

Has anyone experienced that kind of problem?

voip wrote:If the noise cannot be heard through the headphones, then it suggests that, at least internally, the Kronos is probably OK.

Try connecting the headphones to each of the Kronos main L and R outputs in turn, with all other connections removed (apart from mains power) to see if the noise is present there, just to rule out the Kronos' L and R output stages. It won't do any harm to the Kronos. When listened through these outputs, sounds played on the keyboard will sound somewhat different, because they will be in mono, and left and right ears will be out of phase, because you will effectively be hearing each side of the balanced outputs. The important thing is to listen for the presence/absence of the noise.

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I have a noise of the same intensity on the L and R outputs. With headphones it is normal and perfect. I only hear the NOISE on the P10 outputs. What could it be? It's a Korg PS60.

Marmus wrote:In my home studio the Korg Kronos L/R outputs are plugged in a Focusrite Scarlett 18i20 and to the computer. The Kronos is generating lots of noisy.

The problem doesn't come from the cables or the speakers They work fine in other situations.

Strange enough, this happens even if the Kronos is turned off and unplugged from the outlet. When I unplug the cables out of the Kronos L/R audio outputs the noise stops and it starts again as soon as I plug them back in.

Has anyone experienced that kind of problem?

Check and turn down the mic/line level knobs at the back of your Kronos to zero, there are two inputs at the back with dials turn both to zero/MIN.

Easy test is go to sequencer mode (follow instructions below) and listen for it if it is there then the knobs have been turned up. Make sure to raise the gain/volume up on keyboard to high then it is easily heard.


Steps to test if the inputs 1/2 at the back of the Kronos is doing it:-

1- Go to Sequencer mode.
2- Click audio tab.
3- Select a audio track 1-16 any.
4- You will hear a hiss/humm if the audio inputs 1/2 is turned up.
5- Turn down to lowest on inputs 1/2 at back of the kronos the two dials.
6- No hiss or humm but remember to turn them up if you need them with a line device or mic or you will end up with no sound and pulling your hair out again wondering if the input settings are wrong or the inputs are broken.


Seems to come up a lot recently on many forums and social media pages this issue so added here as a reminder for the new users and the not so new users that always seem to forget this one when helping others with a hiss/humm problem and 99% of the time it turns out to be this because some one fiddled with the dials or the Kronos was moved and the dials knocked.

Hi guys, here is a little update to this subject.

I tried other USB cables but the same problem occurred. I changed my USB Hub for a Thunderbolt Hub and tried to plug via USB-A and USB-C without significant result.

I finally bought a high quality shielded USB Cable and the noise disappeared.

The noise was generated by the USB Cable.

I hope this can help others who could encounter the same problem.

Martin C.