Music / Instruments
EHX The Worm Analog Modulation Pedal
A quick guide to using the EHX The Worm analog modulation pedal, covering controls, effect modes, power requirements, and expression pedal setup.
Table of contents
Quick guide from the manual
The EHX The Worm is a multi-functional analog modulation pedal featuring four distinct effects: Modulated Wah, Phaser, Tremolo, and Vibrato. This guide provides essential information on power, controls, and connectivity.
Power requirements
Important: The unit requires the supplied 24V DC (inner positive) / 100mA external power adapter. Do not use batteries. Using an incorrect adapter can cause serious bodily injury, damage the unit, and void the warranty.
Controls
- MODE Rotary Switch: Selects between WAH, PHASER, TREMOLO, and VIBRATO effects.
- RANGE Knob: Adjusts the intensity of the effect. Turning clockwise increases intensity.
- RATE Knob: Adjusts the modulation speed. Turning clockwise increases speed.
- AUTO / MANUAL/EXP Toggle Switch: Set to AUTO for normal modulation. Set to MANUAL/EXP to disconnect the internal waveform and use the RANGE knob or an external expression pedal to sweep the effect.
- STATUS LED and FOOTSWITCH: The LED blinks at the modulation rate when the effect is engaged. If the LED is off, the pedal is in True Bypass mode.
Connectivity
- INPUT Jack: Connect your instrument here (300 kΩ impedance).
- OUTPUT Jack: Connect to your amplifier or the next effects pedal (1 kΩ impedance).
- EXP. PEDAL Jack: Connect an expression pedal or a Control Voltage generator (0–5V only). The expression pedal must use a TRS plug with the tip connected to the wiper.
- 24V PWR Jack: Connect the supplied power adapter here.
Compatibility
Compatible expression pedals include the M-Audio EX-P, Moog Expression Pedal, Roland EV-5, and Boss FV-500L.
Practical help
Common problems
Effect not working or no sound
Ensure the supplied 24V DC 100mA adapter is connected. The unit does not accept batteries.
Expression pedal not controlling effect
Ensure the toggle switch is set to MANUAL/EXP mode and the pedal is compatible (TRS plug required).
Effect intensity or speed not changing
Check the RANGE and RATE knobs. If in MANUAL/EXP mode, the internal modulation is disconnected.
Before use
- Connect the supplied 24V DC power adapter.
- Connect your instrument to the INPUT jack.
- Connect your amplifier to the OUTPUT jack.
- Select the desired effect using the MODE switch.
- Set the toggle switch to AUTO for standard operation.
Specs in practice
- Input Impedance
- 300 kΩ
- Output Impedance
- 1 kΩ
- Control Voltage
- 0-5V range for external control
Model compatibility
- Compatible expression pedals: M-Audio EX-P, Moog Expression Pedal, Roland EV-5, Boss FV-500L.
- Control Voltage input must be between 0V and 5V.
Manual page author
David Miller
Documentation analyst
Organizes user manual content into clear summaries, with attention to model details, product context, and everyday usability.