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Korg N364 noise

Posted: Wed Dec 05, 2018 12:46 am
by ironman
Hi,

I'm a newbie to old synthesizers, guitar is my main instrument, and around a year and a half ago I got a deal for an used Korg N364. The price was way less than Ebay prices, so I pulled the trigger and for a while couldn't be happier.
Everything seemed to be working fine as I usually practice at home at moderate volumes, but after playing through rehearsal PA I noticed a strange digitalish(?) white noise from the keyboard. The Noise follows the main volume slider and is heard in all the outputs.
I've managed to isolate the problem to effects. If I route all the effects from serial to parallel and turn off the volume from the parallel signal, the noise disappears. Simply turning effects globally off won't do this and the noise continues. I've tried to find info for ages, even took the keyboard to a tech who replaced couple of condensers that were getting old. But the noise still prevails.
Just today I found a post here that discussed some noise with Korg M1 and someone said that they had noisy effects. So that left me wondering if it's just something that I'll have to learn to live with and implement better gain staging?


Any help would be greatly appreciated.

Re: Korg N364 noise

Posted: Thu Dec 06, 2018 11:39 pm
by Mooger5
I could be wrong, but that sounds like aliasing noisefloor, sort of common with vintage digital synths. Since it´s noticeable only through the PA system there could be some impedance matching problem. As you say, live with it and implement appropriate gain staging. Synths output low-Z, line signals.

Re: Korg N364 noise

Posted: Fri Dec 07, 2018 12:31 pm
by ironman
Mooger5 wrote:I could be wrong, but that sounds like aliasing noisefloor, sort of common with vintage digital synths. Since it´s noticeable only through the PA system there could be some impedance matching problem. As you say, live with it and implement appropriate gain staging. Synths output low-Z, line signals.
Thanks for your input Mooger. I can certainly hear the noise through my headphones if I put the volume all the way up, although actually playing the thing would be so loud that I wouldn't recommend it. Haven't done it in a while, so I don't remember how loud the noise was but it was there.
If I connect straight to my studio monitors with xlr-cables, there's simply not enough signal from the keyboard to hear the noise even with the volume all the way up. In our rehearsal place I use few meters of low capacitance ts-cables that go straight into a Soundcraft M8 mixers line inputs. I doubt I'm having impedance issues here, but I could be wrong. It wouldn't be the first time. In any case, I tried to search for the N364 output impedance specs, but couldn't find anything.

I'll try to remember to record the noise before we start rehearsals and try to figure out how can I post a link, and possibly some waveform pictures.