Several people have been in touch lately with questions on how to modify the PCB into something it isn't right now. Popular requests are balanced inputs and/or balanced outputs, and DC servo on the outputs.
An explanation of the Muffsy Phono Preamp PCB layout can come in handy for such alterations. And wouldn't you know, here it is:
Finally, if you want to make major modifications, a way of simulating the circuit would really come in handy. Well, here's the Muffsy Phono Preamp LTSpice simulation file.
Since this Spice simulation file contains a correct RIAA signal source, it could be used for any simulation that involves RIAA equalization.