Muffsy RIAA Simulations Part 1: Plausible Scenario

09.03.16 12:54 PM By skrodahl

The RIAA equalization added to vinyl records can and do vary wildly, and you might rightfully say that a phono stage's RIAA compliance doesn't matter too much.


It's still a standard, and it should be one of the considerations when choosing a phono stage.


The Muffsy Phono Preamp uses Wima MKS2 capacitors with 10% tolerance. I have measured a couple of hundred of them, and find that they actually have much better tolerance. They tend to measure about 1 nF below the stated value, so I did some simulations to see what effects that deviation actually has.


This first graph shows a quite plausible scenario, where the values are off by -3%:

Capacitor values: -3%, click on the picture for a larger version

The lowest deviation from the RIAA curve is -0.01 dB, and the highest is +0.16 dB. 


This is realistically what you can expect from the Muffsy Phono Preamp kit in terms of RIAA compliance. Here's the measured RIAA compliance of a Muffsy Phono Preamp with no matched components:

Measured RIAA compliance

These measurements show +0.21/-0.16 dB deviance. Just a smidge more than what we simulated above.


More simulations with really bad capacitor values will come, so stay tuned.

skrodahl