Circuit diagram:

Parts:

R1,R2,R7_______22K 1/4W Resistors
R3,R4,R5_______47K 1/4W Resistors
R6______________4K7 1/4W Resistor
R8,R13________220R 1/4W Resistors
R9______________2K 1/2W Trimmer Cermet (See Notes)
R10___________470K 1/4W Resistor
R11___________560R 1/4W Resistor
R12___________100K 1/4W Resistor

C1____________470nF 63V Polyester Capacitor
C2,C8_________100µF 25V Electrolytic Capacitors
C3,C4,C5________2µ2 63V Electrolytic Capacitors
C6_____________47pF 63V Ceramic Capacitor
C7______________4µ7 63V Electrolytic Capacitor

Q1____________BC560C 45V 100mA Low noise High gain PNP Transistor
Q2____________BC550C 45V 100mA Low noise High gain NPN Transistor

IC1___________TL061 Low current BIFET Op-Amp