Headphones out but the speaker's still playing? Meet SIG OUT and SPKR VOL

The Mach 3 has two independent volume controls: - SIG OUT sets the level of the Line Out / Headphone output. - SPKR VOL sets the overall volume coming from the speaker. They work separately on purpose, so you can send a Line Out feed while using the speaker as your monitor, or run the speaker as your main sound while also listening on headphones. Because of that, plugging in headphones does not mute the speaker. For quiet practice, turn SPKR VOL down and bring SIG OUT up to taste. And if you've got SIG OUT up but hear nothing on your phones, double-check the headphones, the cable, or whatever you've patched the Line Out into.