Passive RIAA Preamplifier
Circuit diagram:Passive RIAA Preamplifier Circuit Diagram
Some of the gain loss in the passive network is then made up by FET Q3. It also has a 51kO drain resistor and is buffered by bipolar transistor Q4 which is connected as an emitter-follower stage. All resistors are 1% tolerance metal film type while the capacitors for equalisation are MKT polyester types. Ideally, the Idss of all FETs should be matched for both channels. Resistors R3 and R8 should be adjusted so that the drain voltage in each stage is between 13V and 14V, to give symmetrical signal clipping. The power supply can be three 9V batteries connected in series. Current consumption is only 3mA for the stereo circuit.
Author: Sam Yoshioka - Copyright: Silicon Chip Electronics