Hifi Preamps for your Record Player

By: skrodahl | October 16, 2018

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.

The PCB itself doesn't really lend itself to any of the modifications above, but you could always try doing add-on boards or roll your own from the open source freely available schematics.

An explanation of the Muffsy Phono Preamp PCB layout can come in handy for such alterations. And wouldn't you know, here it is:

Muffsy PP-4 PCB Layout
The Muffsy Phono Preamp PP-4 PCB Layout

Modifications you can do are changing the input impedance and altering the variable gain. I'm also happy to announce that the gain calculator has been updated to show the output voltage and voltage gain:

Muffsy PP-4 Gain Calculator
Muffsy PP-4 Gain Calculator

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.

Muffsy LTSpice Simulation
Muffsy Phono Preamp LTSpice Simulation