Submitted by Kuosch on Fri, 2020-05-15 - 20:03

Project status: Planning

2020-05-10: Decided to make simulations on different topologies.

Background

RIAA preamps are used to connect a turntable to the rest of the system. The preamplifier is required because of the physical limitations of vinyl records: low frequencies would cause too much movement in the vinyl groove (the groove is not a simple spiral, it is modulated by the audio). To keep the groove in control, a pre-emphasis filter was used before cutting the master disc. This pre-emphasis must be undone when playing the record.

RIAA preamps are not very complicated, there is a standard describing the filter, and several different circuit topologies are widely available for example in datasheets. I have found three different approaches thus far, and I'm going to simulate them all before deciding which to use. The main choice is between passive and active filters.