I've been looking and i see a few products now with a digital volume pots and stuff. I'm wondering how they do it.. i can see from pictures they use surface mount transisters one transistor per step with a resistor to change the volume out put. Does any one know how this could be done. Maybe with a rotoray control of some how ect ect. to turn on each transistor. Id like to try and build one.. So far i have seen the pass labs pre-amp and the conrad johnson pre-amp's and a few others.. Any one got any idea's. ? I don't want to step on any toes but it would be a good project and be able to hear silence when turning up the volume instead of relay's..