Well, this is a JRC4558 opamp with diode clipping. TS! But here is also a TexasInstrument ne5532 used for the clean mixing. The the tone is only effecting the overdrive part so the clean is not affected. Very nice! And this device is a through-hole mounted components. So it is a very good platform for DIY mods if you would like to test different diodes. It is a low cost, but most of it seems pretty good. Caps are good there they need to good. Pots are good for the price. Over all very impressed for the price. The only thing that I have to say is that is on the negative is the feets are too high, the Velcro (not included) does not grab this very well to the pedal board, it is also quite big for modern standards. [You can not have though hole and small]