No Output

[Kesmith1]

Have you confirmed there isn't a problem with the cable? Have you tried a different cable?

Swapping out cables was the first thing I did. The XLR to 1/4 is a new cable. Using the Out 2 with a standard instrument cable gets the same results - a very loud hum with no guitar signal.

 

[Kesmith1]

Guitar amps don't typically have balanced inputs, so there would be no advantage to using balanced outs with them. If you're connecting to balanced inputs on a mixer or power amp, for example, then it makes sense.

For troubleshooting purposes, can you try connecting from out2 to the amp using a standard TS instrument cable? That will help determine what the issue is ...

Yes, to use stereo balanced lines with mixer and recording. I’ve tried the out 2 using standard instrument cable - same result.

 

[fcs101]

You said the headphone out works, so try using a 1/4" instrument cable from that output to your amp just to test that it's not some other problem.

 

[AtomicJeff]

I’ve done zero editing yet so a factory reset does sound like a good option. How would you do that?

Is this a new or used unit?
Here's a good video on factory reset:

 

[unix-guy]

Yes, to use stereo balanced lines with mixer and recording.

Again, do not do this. The jacks are TRS but they are wired specifically for Humbuster use in that case.

Output 2 is not balanced and on page 8 of the manual it explicitly states:

For OUTPUT 2, standard 1/4" (guitar) cables may be used, but there is a better option. HumbusterTM cables can significantly reduce unwanted hum due to ground loops. A Humbuster cable has one TRS end (like a balanced cable) and one TS end (like a guitar cable). The TRS end connects to the FM3. The TS end connects to your amp or other device. Do NOT connect TRS-to-TRS cables or TRS-to-XLR cables to Output 2.

At this point, I would suggest you contact Fractal support. It sounds like you may have a hardware issue. Possibly a loose or disconnected ribbon cable.