Rega Fono MC (MK4) — Moving Coil Phono StageRega builds the Fono MC around a fully discrete input stage using Linear Systems LSK389 FETs not an op amp, not a chip solution, a proper transistor circuit chosen for its noise characteristics at the signal levels an MC cartridge delivers. That matters at the input of a phono stage more than almost anywhere else in the signal chain, because MC output is measured in hundredths of a millivolt and whatever noise your phono stage adds at that point gets