looper/playback pedal schematic

[peterg]

Does anyone have one? TC Electronics Ditto is a good simple looper. Schematics seem to be non existant. All I can find are bypass loopers not playback ones.

[midwayfair]

Madbean's Loophole uses the same chip that's in Zvex's Lo-Fi Junky. The chip was used in old answering machines. It does not sound exactly "good," but it is possible to use it in an analog circuit.

Good playback loop pedals are digital recording devices and not readily DIY-able, and a schematic wouldn't really tell you anything since the DSP won't be there.

[slacker]

Like Jon said you can make a simple looper using answer phone chips, search the forum for "pay back" for another example, these generally only record one loop at a time and don't have features like over dubbing. In theory it's possible to do a few seconds of looping with the Spin FV-1 chip, but this is digital and requires programming, as far as I know no one has made a project that does this.
There's also this http://createdigitalmusic.com/2009/05/wheres-the-party-at-bendable-open-source-8-bit-sampler-now-shipping/ if you fancy something more hardcore.

About the only practical way to DIY something like the Ditto or other commercial loopers is to use a PC with looping software then make or buy a foot controller. It might be possible to use something like the Raspberry Pi to make something more stompbox like. You probably couldn't build something for less than buying a looper though.