RIAA Preamplifier Circuit - Technics SA-210

One of the nicest features of the Technics SA-210 is the built-in phono preamplifier with RIAA equaliser, which allows the owner to connect a record player/turntable. The RIAA preamplifier circuit uses the JRC 4559DD dual operational amplifier IC by the Japan Radio Corporation. Versions of this IC are still available and it is likely that students and hobbyists might want to have a go building it. In the SA-210, they have built this part of the circuit as a separate module vertically oriented and connecting to the main board, and this module receives approximately ±13 V in a split-rail power supply configuration. It appears to be a very good design and the input sensitivity is 2.5 mV/47 kΩ.

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