This single low noise JFET input discrete RIAA stage utilizes a single 2SK170BL in a discrete high gain circuit with a 300MHz PNP driver loaded with a FET current source and 300MHz BJT Class A output. The input FET is sufficiently low noise at 1nV/rt Hz yet provides input impedance isolation of the feedback RIAA stage (an interaction common in non-differential BJT inputs) to eliminate HF gain errors.

The module is fitted standard with 47K//100pF cartridge loading and gain of 40dB. Other loadings and gains are possible by substitution. The equalisation follows the IEC extended bass (below 50Hz) characteristic to 20Hz with a 2 pole rolloff below to reduce 3 - 4 Hz warp intrusion. Also included is the ultrasonic response correction to compensate the HF response for cutter pole response errors, lack of which increases sibilance and edginess on instruments in many designs.

Input Sensitivity

5mV for 500mV out

Input Impedance

47K ohms and 100pF

40dB (1KHz) with other gains possible
Subsonic Filter
14dB @ 3Hz
IEC modified RIAA +/-0.25dB.
Output Impedance
47 ohms
Load Impedance
minimum 10K
30dB at 1KHz
Power Supply
+/-15V DC low noise regulated for best
Current Draw
15 - 20 mA.
51W x 65D x 15H



PCB Only

AU$27 + $5 p&p

Full module kit

AU$62 + $7 p&p

Built & tested

AU$91 + $10 p&p