Mystery noise from Helix stereo XLR

[trhx]

I have stereo XLRs going from Helix straight into 2 inputs on my digital mixer (UI24r) and set the gains to hit about -18 to -12. The 2 mixer channels for my guitar are stereo linked, so the gain levels are the only independent settings.

 

There have been a couple of times where I get a signal of about -24 on only one input while not playing. So far, the fix has been to switch the cables at one end. Doesn't matter whether I switch at the Helix or at the mixer - both signals are zero after I make the switch. Obviously, pretty easy fix (and I can label my cables for specific channels) but I'd like to understand why that happens. Seems like a polarity thing, but I'm just not quite getting it. Can someone tell me why this happens?

 

Thanks.

[Schmalle]

Is your Ground Lift switch engaged?

What kind of interfering signal is it?

[brue58ski]

That sounds more like a mixer issue to me. Have you tried using something else in the mixer's inputs to see if it will duplicate the issue? And just to be clear it only happens on one input, not both? If that's true, again, that sounds like the issue is with the mixer.

[trhx]

I checked the ground lift the last time it happened, but that didn't make a difference.

 

I can't say for sure it isn't a problem with the mixer. Since I have a feeling it's related to the stereo link, I can test with my stereo edrum kit and report back next week.

[waymda]

I use a UI24R and linked stereo channels with my Helix. No problems to date, but depending on the age of the UI24R see reports of chanels failing in the Farcebook communities. I find I run very little channel gain as the UI see's the Helix as hot, even with mic output levels. I've also seen reports of maxing out the UI input gain levels causing system reboots - so its a sensitive thing.

 

I'd test using:

• different linked chanels
• a fresh/clear scene (have seen references to chanel programming getting messed up over time)
• the bottom row of inputs vs the top noting the top row has combi inputs
• the Helix XLRs into a phatom power filter (even if the UI says phantom is off)
• the Helix 1/4 inch outputs into a DI

 

 

[brue58ski]

On 4/30/2024 at 3:23 PM, trhx said:

I checked the ground lift the last time it happened, but that didn't make a difference.

 

I can't say for sure it isn't a problem with the mixer. Since I have a feeling it's related to the stereo link, I can test with my stereo edrum kit and report back next week.

 

The main reason I think it's the mixer is that it happens on one channel only. If it was the Helix then the phenomenon would have switched channels on the mixer when you switched cables. At the very least, I'm pretty sure it's not the Helix.