Korg Forums

Hi there,

Is it normal that there is a small humming / noise sound when the KORG is plugged in. King of resembles a very light airy sound, like an airplane motor in the very distance. Is my KORG prologue broken? I'm really scared it is and I've only just bought it.

I found as well this sound is even louder and more crackly when I plug the USB in, so I have avoided the USB but it's still showing signs of it, but a lot quieter even when I just have it plugged into my interface / and I'm running Ableton. The jack cables aren't broke - they worked fine without any sound issues in my Nord Lead A1 synth, but this... it's awful.

Any help appreciated. Could my outputs be broken?

Might not be the Prologue, most likely electrical ground noise from your studio setup.
I do get a good amount of noise coming from the Prologue outputs. It doesn't change when I plug in the USB. It's not a hum though, more like a low level crackly white noise. Hum is usually ground loop or such like I believe.
Usually I have the Prologue master level up to max and the mixer/audio interface input level as low as possible to reduce noise from the Prologue.
My interface also has a setting for line input level: +4dBu / -10dBV. When I have it on -10 the Prologue is nice and loud but the noise is too. So I keep it on +4. The Prologue manual doesn't state output level specs.


Apparently one solution is to have all your devices plugged into the same multiboard from one wall socket so they all have the same phase AC, I'm not sure about that. But if you have a lot of devices this isn't practical. So may need to find another way to eliminate electrical noise created between devices.
USB creates it's own electrical noise which is what you're hearing. There are ways to eliminate this.

This would be made better if the Prologue had balanced TRS outputs, but unfortunately they are unbalanced TS. Another Korg cost-saving measure I guess.
If Behringer can put balanced outputs in the Neutron I don't see why Korg can't put them in the Prologue.

Thanks so much for the extremely useful response. I'll do some plug switching around and play a bit, and see what I can achieve.