PedalPCB Son of Ben Preamp User manual

Copyright © 2020 - PedalPCB.com Page 1 of 6Son of Ben Preamp
Son of Ben Preamp
Revised 10/26/21
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• Volume
• Drive
• Treble
• Bass
CONTROLS AND FEATURES

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Son of Ben Preamp
Parts List (Page 1 of 1)
LOCATION VALUE TYPE NOTES
R1 1M Resistor, 1/4W
R2 220K Resistor, 1/4W
R3 1M Resistor, 1/4W
R4 1K Resistor, 1/4W
R5 10K Resistor, 1/4W
R6 470K Resistor, 1/4W
R7 470K Resistor, 1/4W
R8 1K Resistor, 1/4W
R9 10K Resistor, 1/4W
R10 100K Resistor, 1/4W
R11 1K Resistor, 1/4W
R12 10K Resistor, 1/4W
R13 47K Resistor, 1/4W
R100 4K7 Resistor, 1/4W
C1 100n Film capacitor, 7.2 x 2.5mm
C2 22n Film capacitor, 7.2 x 2.5mm
C3 250p Ceramic capacitor
C4 470p Ceramic capacitor
C5 10u Electrolytic capacitor, 5mm
C6 22n Film capacitor, 7.2 x 2.5mm
C7 22n Film capacitor, 7.2 x 2.5mm
C8 22n Film capacitor, 7.2 x 2.5mm
C9 2n2 Film capacitor, 7.2 x 2.5mm
C10 10u Electrolytic capacitor, 5mm *Optional (see Page 3)
C100 100u Electrolytic capacitor, 5mm
C101 100n Film capacitor, 7.2 x 2.5mm
D100 1N5817 Schottky diode, DO-41
Q1 J201 JFET transistor, N-channel *Alternate MMBFJ201 (SMD)
Q2 J201 JFET transistor, N-channel *Alternate MMBFJ201 (SMD)
Q3 J201 JFET transistor, N-channel *Alternate MMBFJ201 (SMD)
VOLUME A100K 16mm right-angle PCB mount pot
DRIVE A1M 16mm right-angle PCB mount pot
TREBLE A250K 16mm right-angle PCB mount pot
BASS *** *** * Refer to Page 3
TRIM1 50K Trim potentiometer 3362P-style
TRIM2 50K Trim potentiometer 3362P-style
TRIM3 50K Trim potentiometer 3362P-style
NOTE
C10 was only populated in the rst 100 units.
Newer units omit this capacitor.

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Son of Ben Preamp
Additional Information
Capacitor C10 was only populated in the rst 100 original units. Current production units
omit this capacitor.
Capacitor C10 (Optional)
The original B2M Single-Ganged potentiometer used for the Bass control isn’t a common value and
can be dicult to source. Alternatively a B1M Dual-Ganged potentiometer can be used.
The Son of Ben Preamp PCB layout is designed to accommodate either part.
Bass Potentiometer
B2M Single-Ganged B1M Dual-Ganged
When using a Dual-Ganged B1M
potentiometer the solder pads between
lugs 2 and 3 of the Bass potentiometer
should be left open.
When using a Single-Ganged B2M
potentiometer the solder pads between
lugs 2 and 3 of the Bass potentiometer
should be bridged with solder.
The potentiometer should be installed
into the bottom row of pads.

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Son of Ben Preamp
Schematic Diagram
Adjust TRIM1 to 2KΩ Adjust TRIM2 for 4.0V on Drain of Q2 Adjust TRIM3 for 4.0V on Drain of Q3

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Son of Ben Preamp
Wiring Diagram

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Copyright © 2020 - PedalPCB.com Page 6 of 6Son of Ben Preamp
Son of Ben Preamp
Drill Template
125B Enclosure
Treble Bass
Volume Drive