ParksTool on a Pedalboard — Expression Pedal Setup with the 9F18K1X

The 9F18K1X has a 3.5mm TRS expression pedal input. Combined with TRS MIDI OUT and USB bus power, it's a complete standalone MIDI controller that fits into a pedalboard rig without a laptop anywhere in the signal chain.

Connecting an Expression Pedal

Plug a standard TRS expression pedal into the 3.5mm input on the 9F18K1X. The LED on the port illuminates when a pedal is connected. In the Web Configuration Tool, the expression pedal appears as a separate control — assign it a CC number, set the range, and it's ready.

Calibration: If your pedal doesn't reach the full 0–127 range at the physical extremes, adjust Expression Pedal Deadzone Low and Expression Pedal Deadzone High in Global Variables. These compensate for pedals that don't sweep fully to heel-down or toe-down.

Full Pedalboard Setup

• Power the 9F18K1X from any USB source on your board (power bank, switcher USB port, etc.)
• TRS MIDI OUT to your MIDI-capable pedal, synthesizer, or MIDI router
• Expression pedal into the TRS input
• No computer, no audio interface needed

The 9 faders give you continuous parameter control — volume, sends, effect depth — and the 18 keys handle switching, transport, or anything else you need. Configure everything once in the web tool; the settings persist on the device.

TRS Type Note

Expression pedal TRS wiring varies by manufacturer. If your pedal doesn't behave as expected after connecting, check whether it uses a standard TRS pinout or a reversed one — this is usually documented in the pedal's manual. Most standard expression pedals (Roland EV-5, Boss FV series) work without adjustment.