Maxon OD-808

This guitar pedal does not work well with the low impedance line output typically found on synthesizers. It will only work well with the high impedance output of electric guitars.

Basically you will not get any noticable overdrive effect at all out of this pedal when using it with a low impedance line output, the gain knob will do virtually nothing to the signal. Unless you turn the volume of your synth extremely low and boost/amplify the signal at a later stage, but then you will most likely get undesirable noise and the overdrive effect will still only barely be noticable.

Only the tone and balance knobs will work when using this with low impedance line out, but then the pedal becomes just a lowpass filter with a volume knob and no overdrive effect.

If you want to use this pedal with a synthesizer, or any other low impedance output, then you will need something such as a reamp box, to convert your low impedance line out to a high impedance instrument output.