Did I unintentionally make use of the humbuster outputs on my FM9? 1/4" noise is GONE!

[strabes]

I record my FM9 with USB but I monitor it with two analog inputs on my interface so I can control the monitoring levels with my interface's control software (TotalMix FX) and don't need a DAW open to practice.

Until recently I used XLR for this but in order to free up the mic pres on my interface I switched to unbalanced 1/4". XLR is silent but unbalanced 1/4" has quite a bit of high end noise, probably coming from all the stuff I have connected with USB. Even XLR to TRS had noise. Here's a short video of the noise, admittedly with the FM9 turned up extremely loud in TotalMix FX. You can even hear its LEDs turning on and off in the 2nd half of the clip.

When reading my interface's manual I realized its 1/4" inputs send the ring to ground:



That reminded me of Humbuster wiring...

...so I realized that electrically the wiring is the same as a humbuster cable i.e. hot tip, ring & sleeve to ground on the "amp/interface" end.

I thought "no way is this going to work," but I connected a 1/4" TRS cable from FM9's 1/4" Output 1 to my interface's 1/4" inputs and the noise is completely gone. Using XLR to TRS does have the noise so the noise cancellation must be due to the humbuster outputs killing the noise! Another Fractal innovation coming in clutch!

 

[Rumbletone]

That makes sense.

I suspect they don’t recommend doing this because not all gear is wired that way, and in particular pedals with batteries that use the typical input jack switching won’t work at all with a TRS into the input. And balanced inputs would connect one side of the balanced input to the humbuster ring on the Fractal output … and I don’t know what would happen then?