Korg Forums

Darryll · Joined: 11 Sep 2012 Posts: 45 Location: North Carolina

Hello All. I have a simple home studio setup. I have both a Kronos 88x and 61. My interface is a Liquid Saffire 56. I am getting an annoying audio 'buzz' when everything is idle (i.e. no music playing, not playing the keybds, no software running, etc.). Even if the Kronos is turned off, I still get the buzz. If I UNPLUG the Kronos power cord, the buzz stops. Plug the power cord back in (Kronos turned OFF), the buzz returns. I tested this with my Kronos 61: (SAME PROBLEM). I tested this with my Kurzweil PC88: (No buzz, hum, nothing). Quiet as a house mouse. All tests were with the same two L/R Monster keyboard cables. I simply moved the L/R cables from one keyboard to the next. No changes to the interface inputs, settings, etc. All three boards are plugged into a Monster Powercenter Pro800 surge strip.

I think more specific details are mute because simply moving the L/R cable from the Kronos to the PC88 solves this issue. The PC88 can be turned on with me playing it and NO buzz or hum. Very quiet as expected. So the problem must be with the Kronos boards. Correct?

I love the Kronos and this is the only issue that I am having with them BOTH. Please help!

StephenKay · Posted: Sat Jan 02, 2016 4:25 am Post subject:

You might try a ground lifter on the power cord of various pieces of gear - the little plug with 3rd pin ground missing.
_________________
Stephen Kay - KARMA Developer • Karma-Lab - karma-lab.com

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

Stephen is right, it sounds like a grounding problem. Using a ground lift plug isn't the safest way to deal with it though, electrical devices have a ground for a reason. A closed system only needs one grounding point (or actually requires a single grounding point to work properly) but if you switch cables and interrupt the system it could be dangerous if you lift ground here and there. Especially if you're having problems now.

To start off, make sure you're using a single wall socket (with splitters/extensions as needed) for all interconnected gear. See if that does anything. If not, it's better to lift ground on an audio lead than on a power lead. You can do this with DI boxes or in a studio situation by permanently cutting the ground on the audio leads.

Thoraldus · Posted: Sat Jan 02, 2016 4:23 pm Post subject:

StephenKay · Posted: Sat Jan 02, 2016 6:23 pm Post subject:

Darryll · Joined: 11 Sep 2012 Posts: 45 Location: North Carolina

Thank you SanderXpander. It does seem to be a ground issue. The PC88 has a two prong pwr cord and that is why I have no problem with it (I assume). I tried the two prong adapter on the Kronos and the hum is almost gone. I understand DI boxes but had to research your note about "...permanently cutting the ground on the audio leads". I think I'm good to go now and should be able to trace down & eliminate the remaining subtle hum in the system.

Thanks a million!

Dan Stesco · Posted: Mon Jan 04, 2016 7:00 pm Post subject:

Hi !

Please check the input level and input Mic/Line switch.
Usually the hi level of mic input generate the noise.

Best,
Dan

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

Also a good point by Dan, although that's usually more hiss than hum.

Glad you are on the right track now! If you are planning to cut ground on an audio cable it would be nice to use a balanced connection. The Kronos has balanced outputs, your Liquid Saffire 56 has balanced inputs on XLR. So you could use TRS to XLR cables.

Remember that a device that has ground should be grounded! Unless you're very sure of what you're doing, it's not safe to simply unground electrical connections (read: use two-prong adapters where there should be three).

Darryll · Joined: 11 Sep 2012 Posts: 45 Location: North Carolina

SanderXpander/Dan/StephenKay,

Thanks guys! The humming & crackling has ended Smile

. It was two issues 1. Grounding 2. WiFi Router (duh!).

(Just for testing) I lifted the ground of the Kronos via a two prong adapter. Still got a little hum. Plugged keyboard, Saffire 56, and computer into one surge protector; and then plugged that surge protector (via a two prong adapter) into a Monster Powercenter Pro800 surge that is plugged directly into the wall outlet (no adapter). Still got 'a little' annoying hum w/crackling. Moved the WiFi router that was close to the monitors and voila. So the issue was 90% Kronos grounding and 10% network Router interference.

Again, I'm new at this so forgive the dumb question(s). I am safe to leave the Kronos' power cord plugged in via a two prong adapter because the Kronos is also grounded via the balanced audio cables connected to the Sapphire 56, correct?

Thanks guys!!!!

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

Eerrrrrmm if you never remove a single cable from a socket that is in theory a safe setup. But if you remove the audio cables from the Kronos or even the Fireface FW cable from the computer you potentially unground part of the system. I would call it a stop-gap solution. Much better to cut the ground on the audio leads. Since it's a balanced connection, they should still have the same noise canceling effect anyway.

krossuser4 · Full Member Joined: 13 Nov 2014 Posts: 112