Colorsound Dipthonizer

[GREEN FUZ]

Found this on ebay and was immediately intrigued.

http://cgi.ebay.co.uk/Colorsound-Dipthonizer-Fuzz-Filter-70s-vintage-v-rare_W0QQitemZ230189437891QQihZ013QQcategoryZ22669QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Anyone familiar with this pedal?
At that price it looks ripe for replication. Besides that it seems to offer a lot of scope for a variety of unique sounds.
I can`t really make out what IC`s are being used but the parts count is relatively low.

Has anyone attempted a workalike or possibly even have a schematic for this pedal?

An old thread suggesting it has been attempted, that seems to have fizzled out a few years back.
[url][http://www.diystompboxes.com/smfforum/index.php?topic=19563.0/url]

[R.G.]

It's really not much mystery. See the articles at GEO on the Sing-wah and how to make a way more vocal.

There are two bandpass filters in there. The switch selects a number of presets for sweeping the filters from one vowel range to another. The fuzz gives you more harmonics to work on.

If I were designing a device like that, I'd use two LM13700's for two state variable bandpass filters, then drive them with a control voltage for the sweep. A simple set of sweeps might be done analog, but a PIC would give a lot more flexibility.