Korg Forums

I had a listen to your audio file, and if I heard it correctly, the noise is after you finish playing but stops after you turn off toward the end?
Interestingly, the noise I heard sounded familiar and may not be generated analog noise or cabling, but sounded like software generated, or at least causing settings in the audio interface hardware to produce noise out of the Kronos.
I say this because it sounds a bit like a noise I get from time to time depending on the program that is selected. I've traced it occasionally to the lesley or rotor speaker effect.
I don't know if you've analysed any difference in the noise after doing different software operations on the Kronos, but I just thought I'd put my two cents worth in, seeing as you're a bit mystified after focussing on audio output hardware.

Chris

Tracking the cause of these sorts of problems is not easy.

It does sound like there could some sort of interaction between devices, or an intermittent connection somewhere. You mention using the M3 in the same situation and had no problems. The question is how similar is the situation recently to the one before? Were the power sockets used the same fixed ones in the wall, and the same extension cables? Were the cables laid out in exactly the same way? When you hear the noise over the PA, could you also hear the noise in headphones connected directly to the Kronos? This last test is important and could tell you a lot, since the headphones are "independent" of any power supply, and therefore should not be part of any hum loops.

Is there continuity between mains input ground pin and the Kronos' case, e.g. to a screw head? This can easily be tested with a multimeter. There should be no continuity between the "sleeve" of the output jacks and mains ground.

It is worth removing the bottom cover and checking all the inter-board connections are good. Just "wiggling" them a bit could make a difference, especially if the noise is caused by a poor connection. Do a visual inspection of solder joints, especially in the audio path.

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I had a similar problem with my first Kronos, after testing and help on this forum it was thought it was a ground loop problem.

The Kronos got replaced for another reason and the replacement didn't have the noise.

What happens if you use outputs 3/4 instead of 1/2? (Use the Global Audio page's L/R Bus Indiv. Assign parameter to duplicate the stereo outputs on 3/4.)