User Manual for EHX Swello Attack Envelope Pedal

Quick guide from the manual

The EHX Swello is a compact pedal designed to create polyphonic swell and reverse effects by slowing the volume envelope of your instrument. It also features a low-pass filter with two configurable resonance settings. The unit requires a 9VDC center-negative power supply (100mA) to function, even in bypass mode, as it features buffered analog bypass.

Controls and Jacks

• VOL: Adjusts the output volume.
• ATTACK: Controls the attack envelope time. Turning clockwise increases attack time, producing a slower swell, reverse effect, or filter sweep.
• FREQ: Controls the cutoff frequency of the low-pass filter. If filter modulation is enabled via the MOD knob, this sets the maximum frequency. The filter is disabled when the LED is green.
• MOD: Controls the depth and direction of the filter envelope. The center (noon) position disables filter modulation. Clockwise creates an upward filter sweep; counterclockwise creates a downward filter sweep.
• FILTER Button: Enables the low-pass filter and selects resonance. Green: Disabled. Orange: Low resonance. Red: High resonance.
• Footswitch and Status LED: Engages or bypasses the effect. The LED color indicates the filter state.
• Input/Output Jacks: Standard 1/4 inch instrument connections.

Resonance Adjustment

You can independently adjust the resonance (Q) for the orange and red filter modes:

1. Press and hold the FILTER button for two seconds until the LED blinks to enter Resonance Adjustment mode.
2. The VOL knob controls the resonance for orange mode.
3. The ATTACK knob controls the resonance for red mode.
4. You can switch between filter modes using the FILTER button while in this mode.
5. To save and exit, press and hold the FILTER button for two seconds until the LED stops blinking.

Factory Restore

To reset the Swello to factory default settings:

1. Power down the pedal.
2. Press and hold the footswitch while reapplying power.
3. Continue holding the footswitch for about two seconds. The LED will cycle through all three colors twice before settling on green.
4. Release the footswitch.

Technical Specifications

• Power Requirements: 9VDC, 100mA, Center-Negative.
• Input Impedance: 2.2MΩ.
• Output Impedance: 680Ω.
• Max Input: +1.5dBu.
• Max Output: +2.1dBu.