This is a modified clone of the strange, old, out-of-production Roland Funny Cat. If you want to see what an original one looks like, click on the OTHER COOL STUFF link, at the left, and scroll down a bit. The original circuitry was deciphered with much great help from the likes of Rob Strand, R.G. Keen, Mark Hammer, et al, and the rest of the cool folks at Aron’s DIY Stompbox Forum. In fact, if you want to see what makes the Funny Cat tick, check out R.G.’s Roland AG5 Funny Cat article at GEO. And, if you want to see some pictures of an original issue Funny Cat, Check ’em out here, on the IDEAS page.
You may be noticing that the clone I made has quite a few more knobs than the original. Well, I said it was modified, didn’t I? Now, let me see if I can remember… Referring to R.G.’s Funny Cat article… In addition to all the standard controls…
I added two 10Ka pots as input and output level controls.
I replaced R10 (47K) with a 500Ka pot, acting as a (sort of) mid-range sweep control.
I added a 500Ka pot in series with each of the two 100K feedback resistors (Rfbb and Rfbc, on U2A and U2B, respectively). One acts as a (sort of) high sweep control, and the other acts as a (again, sort of) low sweep control. These sweep controls have a huge impact on the sound.
I added a Range switch that alternates between 220nF and 680nF caps at C3.
I added a Gain switch that alternates between 470K and 2M feedback resistors at Rfba.
I replaced R16 with a jumper for slightly higher output level from the Harmonic Mover section.
I did not make this a stompbox, per say… No stompswitch. As freaky as this thing can sound, I figured it would mostly be a studio toy. So, it just has the SDS/normal and the Harmonic Mover/normal toggle switches. But, I have to say… It’s probably the most vocal sounding envelope filter/auto-wah type pedal I’ve ever played, let alone built myself. 🙂