New Helix Floor (two different units) - Hissing ONLY on 1/4" out / send

[bharrell91]

Hey all,

 

I opened a support ticket but figured I'd throw this here. I bought a helix floor last week, absolutely love it. Was mostly using the headphones output last week which was great, but I was doing a little recording yesterday and threw two 1/4" outputs into my PreSonus AudioBox 96. There's a substantial hiss coming out of those. It also hisses when plugged into two different amps and directly into my studio monitors.

 

XLR out is completely silent, so is the headphones jack. Guitar Center offered to exchange it, so I did. Re-updated the firmware to 3.70 and hit the factory reset after, same issue with the second unit.

 

I tried the following things:

 

Troubleshooting steps:

- Tried plugging into two different amps -- both had the same hiss

- Tried plugging directly into my studio monitors -- still hissed

- Tried different 1/4" cables -- No change in hissing

- Tried using a Send block instead of the output block -- still hissed

- Tried toggling the lift/ground switch -- no change in hissing

- Tried adding a noise gate on the input block -- no change in hissing

- Tried toggling instrument/line on the Global Settings -- no change in hissing

- Tried factory reset on current firmware -- no change in hissing

- Tried plugging Helix into a different circuit -- no change in hissing

- Tried plugging Helix directly into the wall -- no change in hissing

- Tried removing the USB cable -- hissing INCREASED

- Tried different USB cable (helix and audio box) -- no change in hissing

- Tried turning the Guitar input pad on -- minimal change in hissing

 

Any thoughts? I can use XLR for now but I don't want to lose the 1/4" out (or sends...)

[theElevators]

Since 2 Helixes are exhibiting the same problem, then something else besides the Helix hardware is most likely the issue.

 

1/4" are unbalanced and are susceptible to noise.  XLRs are balanced--noise cancellation.  Maybe your space is just noisy... are the 1/4" cables too long?  Are they old? 

 

In reality, if 1/4" and XLR are set at the same output level, the sound coming out should be pretty much the same, and the hiss shouldn't exist.  Do you have Global EQ that you are applying to 1/4" but not XLR or vice versa? 

 

Out of curiosity, is the hissing always there, or only on high gain amps?  Could it be that you built your presets so that it's outputting different stuff to XLR vs. 1/4"?  Or is your output set to "Multi"? 

 

Try having your Helix plugged into a completely different electrical outlet, like from another room, while keeping everything the same.  Try taking your helix, monitor to another house.  Sometimes there can be incurable ground loop/hiss/buzzing that can only be solved this way (been there several times).  I posted about this before: several times I had the worst single coil 60 cycle (in the US) and 50 cycle (in Germany) hum even when running my guitar in humbucking mode, that was 10 times louder than usual.  If I turned down my guitar, the hum went away.  The only thing that completely eliminated the noise was running the extension cord from the opposite side of the stage where there was another electrical outlet, and running my Helix through that power source -- dead silent. 

 

Good luck!

 

 

[datacommando]

On 12/30/2023 at 1:57 AM, bharrell91 said:

 

Any thoughts?
 

Hi,

 

If this is happening on two different brand new units, then my guess it’s not a Helix issue, but something else, possibly your electrical supply.

 

Check out the suggestions from @theElevators in the post above.

 

Maybe, if you could upload an audio clip of the “hiss” it may help in narrowing down the possible cause of the problem.

[bharrell91]

Thanks to both of you!

 

Quote

Out of curiosity, is the hissing always there, or only on high gain amps?

------

Maybe, if you could upload an audio clip of the “hiss” it may help in narrowing down the possible cause of the problem.

 

Always there. I attached an audio file of the hissing (unaltered, noise floor around -45db), that's without a guitar plugged in on a blank preset. With a guitar plugged in, it's the same.

 

Quote

are the 1/4" cables too long?  Are they old? 

 

I forgot to mention in the OP that my old HD500X is dead quiet with these cables / in this room into the audiobox / amps. I've tried different circuits that are in this room, albeit not a different room altogether.

 

Edit: I also just discovered while recording this clip that the hissing is there with the unit off but 1/4 plugged into the unit. Unplugging from the unit (still plugged into the audiobox) kills the hissing.

 

[theElevators]

OK, ground loop for sure!  FYI, I get the same exact sound when I have the USB cable plugged into the Helix (powered on or powered off), while the computer is connected to monitors.  The USB cable just does some weird sh to everything else but the Helix, which is not even powered on.  Since the Helix is not even running, where's the hum coming from?  IDK.  The buzzing develops after about 30 seconds of me connecting the USB cable to the Helix.  Something weird with the wiring, inductance, resistance, who the f knows.  In my apartment, I have no desire to investigate what exactly is causing the noise, but I know what to do to circumvent the noise--unplug the USB cable when not in use--I have a USB hub and I just pull out the cable and I can clearly hear the noise stopping when I do that.

 

Please try the things I outlined in the previous post and let us know!  Eliminate as many factors as possible--your computer can be also affecting things!  I am confident the issue is with wiring/ground loop. 

[datacommando]

On 12/30/2023 at 8:13 PM, bharrell91 said:

Edit: I also just discovered while recording this clip that the hissing is there with the unit off but 1/4 plugged into the unit. Unplugging from the unit (still plugged into the audiobox) kills the hissing.

If, as we seem to suspect, this noise is a ground loop, then one solution that has been recommended several times by forum contributor @rd2rk is to use a hum eliminator, for example - Pyle PHE400 - $30 on Amazon. He says this works to silence both audio and USB hum.

Maybe he will chime in to verify that.

 

Hope this helps/makes sense.

[bharrell91]

Interesting. I wonder why it affects the Helix and not the HD500x or amps. FWIW the hissing gets louder when unplugging the USB from the computer.

 

I bought a hum eliminator, should be here Wednesday. If it really is a ground loop I doubt anywhere else in our 1970s home is gonna be any better without it, so I'll wait and try that before trying other rooms.

 

 

[bharrell91]

Eliminator came early, that did the trick. Made things in general a lot quieter but that seems to be able to be compensated for. Thanks guys, i really wouldn't have thought ground loop here given everything else that's quiet.

 

 

[GotMetalBoy]

On 1/2/2024 at 6:18 PM, bharrell91 said:

Eliminator came early, that did the trick. Made things in general a lot quieter but that seems to be able to be compensated for. Thanks guys, i really wouldn't have thought ground loop here given everything else that's quiet.

 

 

Which hum eliminator did you get? I bought the Pyle PHE400 and Pyle PHE300 and both of them changed the frequency response and sounded like it used a low pass filter and removed some of the high end and lowered the output, so I returned them.