My first pedal with success from a kit of Musikding http://www.musikding.de/The-Screamer-Overdrive-kit
Is a TS808 Tubescreamer with an additional switch, it is used to switch between symmetrical and asymetrical diode (1n4148) clipping.
(https://lh6.googleusercontent.com/-UsB3hK3T6sQ/UpEpSJoxldI/AAAAAAAAAMs/wzM1NCv_yv0/w1242-h928-no/Photo+10-04-12+12+18+45.jpg)
(https://lh5.googleusercontent.com/-RVw6ujcKEjI/UpEpStYWAnI/AAAAAAAAANk/5_QsqkRNYyU/w1242-h928-no/Photo+10-04-12+14+05+22.jpg)
(https://lh5.googleusercontent.com/-XD7JFdbbCOU/UpEpTaPRrqI/AAAAAAAAAM8/mQemm1BciaE/w1237-h928-no/IMG_3860.JPG)
(https://lh6.googleusercontent.com/-C0SmGdeq89k/UpEpUfHaL2I/AAAAAAAAANE/n_sVmxZB_04/w1237-h928-no/IMG_3870.JPG)
(https://lh3.googleusercontent.com/-mA0Lwb6fZRM/UpEpVWl5mmI/AAAAAAAAANQ/Ds5H1wXtMgo/w1237-h928-no/IMG_3894.JPG)
Great swirly action!
More swirly goodness. I love that look.