Tone control - Graphic Equaliser

P1_________________10K Linear Potentiometer
P2_________________10K Log. Potentiometer
R1,R2______________68K 1/4W Resistors
R3________________680K 1/4W Resistor
R4________________220K 1/4W Resistor
R5_________________33K 1/4W Resistor
R6__________________2K2 1/4W Resistor
R7__________________5K6 1/4W Resistor
R8,R18____________330R 1/4W Resistors
R9_________________47K 1/4W Resistor
R10________________18K 1/4W Resistor
R11_________________4K7 1/4W Resistor
R12_________________1K 1/4W Resistor
R13_________________1K5 1/4W Resistor
R14,R15,R16_______100K [...]

The Preamp sensitivity and overload margin were designed to cope with most modern music programme sources like CD players, Tape recorders, iPods, Computer audio outputs, Tuners etc. The source selecting switches and input connectors are not shown and their number and arrangement are left to the constructor’s choice.
To obtain a very high input overload margin, [...]

The Bass Boost section provides two switchable levels of Bass enhancement. The input audio is first low-pass filtered by a second-order LPF, whose cutoff frequency is 100Hz. The LPF is built around IC2C and IC2DThe output of the LPF is given to a MUX based on a CD4052. This mux can choose between ground, an [...]