FDBCK: This control has a dual function; in addition to adjusting the amount of feedback in the chorus circuit, it also controls the depth of the chorus. There’s a lot going on within this one knob both in terms of individual function and interactivity, and different settings yield much more varied results than normal. It invites you to step into the hole and shut the door behind you.

MIX: This is your standard wet-dry blend; all the way down is your clean signal run through the Sinkhole’s onboard preamp, and all the way up is all reverb, all the time.

MOD: This controls the rate of the chorus modulation. Setting this control to the minimum slows the LFO down to a barely-discernible rate. Increase for a more dramatic effect.

VERB: This adjusts the decay time of the reverberated signal. Turning this up to the maximum gives you near infinite sustain.

VOL: Adjusts the gain of the onboard preamp. You can use this as a fine clean boost with or without the reverb, if you wish. At very high settings, your particular combination of guitar and other pedals may cause the preamp to slightly clip. If you run the Sinkhole at 18v, this is not an issue.

TRUE BYPASS/BUFFER SWITCH: This switch is internal and requires removing the backplate to access. Do you want your reverb trails chopped off the second you switch the Sinkhole off, or do you want them to continue ringing out even after the pedal is disengaged? For the former, select true bypass (T.B.). For the latter, buffered (BUFF.) mode. The unit ships as stock with buffered mode selected.