EP Booster

COMPONENT LIST

PCB           
PCB               PCB EP BOOSTER

Capacitors
C1    47n        47NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C2    10u        10UF 50V ELECTROLYTIC CAPACITOR 5X11MM
C3    10u        10UF 50V ELECTROLYTIC CAPACITOR 5X11MM (Original)
C3    0.1u       0.1UF 50V ELECTROLYTIC CAPACITOR 5X11MM  (Remove more bass)
C4    100u      100UF 35V ELECTROLYTIC CAPACITOR 6X11MM
C5    3.3n       3.3NF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C6    10u        10UF 50V ELECTROLYTIC CAPACITOR 5X11MM
C7    10u        10UF 50V ELECTROLYTIC CAPACITOR 5X11MM
C8    47u        47UF 25V ELECTROLYTIC CAPACITOR 5X11MM

Diode            
D1    1N4148      1N4148 SWITCHING SIGNAL DIODE

Transistors            
Q1    J201          SMD SOT-23 J201 JFET N-CHANNEL TRANSISTOR
Q2    2N5088     2N5088 GERENAL PURPOSE TRANSISTOR

Resistors            
R1    1M        1M OHM 1/4W 1% METAL FILM RESISTOR
R2    33k       33K OHM 1/4W 1% METAL FILM RESISTOR
R3    1M        1M OHM 1/4W 1% METAL FILM RESISTOR
R4    50k Trimmer       50K TRIMMER POTENTIOMETER
R5    4.7k      4.7K OHM 1/4W 1% METAL FILM RESISTOR
R6    1k         1K OHM 1/4W 1% METAL FILM RESISTOR
R7    15k      15K OHM 1/4W 1% METAL FILM RESISTOR  (Original)
R7    33k      33K OHM 1/4W 1% METAL FILM RESISTOR  (Remove more treble)
R8    10k       10K OHM 1/4W 1% METAL FILM RESISTOR
R9    1M        1M OHM 1/4W 1% METAL FILM RESISTOR
R10   10k       10K OHM 1/4W 1% METAL FILM RESISTOR
R11   10k       10K OHM 1/4W 1% METAL FILM RESISTOR
R12   47k      47K OHM 1/4W 1% METAL FILM RESISTOR
R13   100       100 OHM 1/4W 1% METAL FILM RESISTOR

Potentiometer            
GAIN    10k-C        10K OHM ANTI-LOG POTENTIOMETER

Switches (top mounted)
S1 (Bass)       MINI TOGGLE SWITCH SPDT ON-ON
S2 (Treble)     MINI TOGGLE SWITCH SPDT ON-ON

Switches (inside mounted)
S1 (Bass)       MINI SLIDE SWITCH SPDT ON-ON
S2 (Treble)     MINI SLIDE SWITCH SPDT ON-ON

SCHEMATIC

PCB

BIAS

Adjust R4 for biasing. The original value of R4 is 8.2k Ohm.

MODIFICATIONS

The original bass and treble switches do not have noticeable effect. To remove more bass, reduce C3 capacitance (e.g. 0.1 uF). To remove more treble, increase R7 resistance (e.g. 33k).

SWITCHES

The PCB allows to mount 4.7mm pitch switches inside the enclosure. 

S1 (Bass)       MINI SLIDE SWITCH SPDT
S2 (Treble)     MINI SLIDE SWITCH SPDT

If no switches are required, no need to mount C4 and R7.