More Gain? Less Gain?

A project log for Muffsy Phono Preamp PP-2

An Improved AudioKarma CNC Phono Stage

skrodahlskrodahl 04/01/2015 at 09:370 Comments

The nice thing about DIY is that you can adapt it to your exact needs. This even goes for the gain on the Muffsy Phono Preamp.

Click this link for more details on the gain stages.

Here's more information on considerations when choosing gain.

The variable gain in this circuit is set by the switches on the right hand side named "GAIN-L" and "GAIN-R". They choose one of the 150R and 300R or connects them in parallel.

The switches must be set the same for both channels, and these are the standard gain options:

By changing these two resistors, you can get other gain levels.

This is what you get by replacing them with 120R and 220R:

If you replace the 150R resistor with a 100R one, you get these gain options:

Things to note:

Resources for calculating gain: