How to built  Skema FET Audio Mixer and Switch Circuit Diagram. all you need part  PARTS LIST
R1 1MΩ

R2 47kΩ
R3 47kΩ
R4 1MΩ
R5 47kΩ
R6 47kΩ
R7 47kΩ
VR1 50kΩ
VR2 50kΩ
C1, C2, C3 4.7µF 16V
C4 100nF (104)
C5 47nF (473)
C6 47nF (473)
Q1 BF245 or 2N3819
Q2 BF245 or 2N3819
S1, S2 Switch
Junction-FETs such as the BF245 or 2N3819 already popular in HF circuits but it can also applied to LF circuits.