Buzz/Hum/Noise When Using Helix Floor Effects Loops 1 and 2

[barish]

Hey y'all I'm in a bit of a quandary here. I've had my Helix Floor for years and in the past used the effects loops for incorporating external pedals into my presets without issue but now I'm getting a crazy amount of noise which sounds like a grounding issue. If I plug my guitar in directly to the pedals and then out into the Helix input everything sounds perfect. Here's a rundown of the chain before I continue.

 

Guitar: Fender AVRI 62 Jazzmaster

Guitar In Pad Off

Auto Impedance On

Noise Gate on @ -48dB

FX Loop 1: Walrus Mira Optical Compressor

FX Loop 2: Jackson Audio Golden Boy Overdrive

FX Loop 3/4: Strymon BigSky (Stereo)

Pedal Power: CIOKS DC7

AC Power: Black Lion power conditioner into sine wave UPS

 

The BigSky has always been in FX Loop 3/4 and has never caused any problems. Previously I had an Origin Effects Cali76 Deluxe Compressor in FX Loop 1 without issue but sold it last year and just picked up the Mira this week.

 

The noise is slightly apparent if only the Mira loop is on and gets wild when the Golden Boy overdrive is turned on after it, but If I go Guitar>Mira>Golden Boy>Helix Input all the noise is gone even with both pedals on. Furthermore, when the pedals are in the loops and I touch their metal casings the noise gets slightly quieter which is why I thought it was a bad cable or grounding issue, but I checked all the cables with a tester and it also doesn't affect anything if I touch the pedals when they're in serial direct to the Helix input.

 

Troubleshooting Steps Taken:

• Confirmed all loops are set to Instrument level in global settings
• Tested all cables used - no issues detected
• Engaged the built-in ground lift button - issue persists
• Swapped the loops used for both pedals (1<>2) - issue persists
• I thought maybe the noise was because the Mira is true bypass and the FX loops weren't properly buffering the signal so I tossed a PolyTune in front of it in the loop but that didn't help
• Put both pedals connected in serial in a single loop - issue persists in both loops 1 and 2
• Swapped DC power cables connected to CIOKS - issue persists
• Tried using 4x brand new Mogami 1/4" instrument cables to connect the loops - issue persists and now my room is a cable nest as well
• Confirmed BigSky loop had no noise issues by setting return mix to 100% with a 100% wet reverb.

 

I'm at a complete loss here. I've attached audio files to demonstrate the difference between going pedals straight into the Helix and using the loops, as well as the preset file I was working off.

Helix V8 BigSky.hlx