- controls the sweep in manual (fixed wah) mode
- controls the filter attack in auto mode
- controls the depth of the sweep in auto mode
- switches between manual or envelope filter mode
No forum threads about this effect yet.
- DOD 440 Envelope Filter
- General Guitar Gadgets DOD 440 Envelope Filter Replica
- Tone Factor 442 Analogue Filter
Here's some code to post a link with image on forums, eBay, websites,...