The most famous pedal in the auto filter genre is the Boss FT-2, which sounds superb, but $500 barely buys you one. This is a similar kinda deal, driven by some superb quality guts and choc full of saucy funky tones. It's pretty easy to dial in all manner of saucy auto-wah sounds, the perfect aural companion to a bed of roses and some scented candles. Very enjoyable indeed.

Model: Maxon AF-01 Auto Filter
Made: Japan, 1985 approx (serial 171721)
Type: dynamic filter
Power: standard 9v negative supply
Switching: buffered bypass
Equivalent new street price (approx): n/a
Mods: none
Accessories: no box or manual
Condition notes: used, few scuffs and marks, ully functional. Overall: good condition