Box of Metal

The Box of Metal is a high-gain distortion pedal great for metal and hard rock.
Steps

Created by DHEA
Status: Active
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Designators and components Step 2 of 5

COMPONENT LIST 

PCB
BOX OF METAL DIY PCB GUITAR EFFECT

Capacitors        
C1    22n      22NF 0.022UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C2    10u      10UF 35V 105C JRB RADIAL ELECTROLYTIC CAPACITOR 5X11MM
C3    22n      22NF 0.022UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C4    1n        1NF 0.001UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR 
C5    10n      10NF 0.01UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C6    22n      22NF 0.022UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C7    22n      22NF 0.022UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C8    100n    100NF 0.1UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C9    2.2n     2.2NF 0.0022UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C10    22n    22NF 0.022UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C11    22n    22NF 0.022UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR
C12    10u    10UF 35V 105C JRB RADIAL ELECTROLYTIC CAPACITOR 5X11MM
C13    100u  100UF 35V 105C RADIAL ELECTROLYTIC CAPACITOR 6X11MM

Diodes        
D1    1N4739A    1N4739A 1N4739 ZENER DIODE 9.1V 1W
D1    1N4001      1N4001 DIODE 1A 50V

IC        
Q1    BS170     BS170 BS170RLRAG MOSFET N-CHANNEL 60V 0.5A
Q2    BS170     BS170 BS170RLRAG MOSFET N-CHANNEL 60V 0.5A
Q3    BS170     BS170 BS170RLRAG MOSFET N-CHANNEL 60V 0.5A
Q4    BS170     BS170 BS170RLRAG MOSFET N-CHANNEL 60V 0.5A
Q5    BS170     BS170 BS170RLRAG MOSFET N-CHANNEL 60V 0.5A

Resistors        
R1     1M        1M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R2     2.2M     2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R3     2.2M     2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R4     1k        1K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R5     5.1k      5.1K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R6     2.2M     2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R7     1.2M     1.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R8     2.2M     2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R9     2.2M     2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R10    5.1k    5.1K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R11    470k   470K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R12    2.2M   2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R13    2.2M   2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R14    5.1k    5.1K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R15    220k   220K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R16    2.2M   2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R17    2.2M   2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R18    5.1k    5.1K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R19    Jumper (solder a cable over the footprint pads)
R20    2.2M   2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R21    2.2M   2.2M OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R22    5.1k    5.1K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R23    47k      47K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R24    100k    100K OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
R25    100     100 OHM 1/4W 1% METAL FILM RESISTOR ROYAL OHM TOP QUALITY
BIAS   5k      5K OHM TRIMMER POTENTIOMETER CERMET 1 TURN 3362P

Potentiometers        
GAIN           5k-C         5K OHM C5K 5KC ANTI-LOG TAPER POTENTIOMETER
VOLUME      100k-A      100K OHM LOGARITHMIC TAPER POTENTIOMETER
BASS           1M-A        1M OHM LOGARITHMIC TAPER POTENTIOMETER
MID             20k-A       20K OHM LOGARITHMIC TAPER POTENTIOMETER
TREB           250k-A     250K OHM LOGARITHMIC TAPER POTENTIOMETER

PCB

Note: there is a missing track on DHC12 PCB version, solder R22 and R23 pads as indicated in the following image.

 

SCHEMATIC

BIASING

Adjust Q5 gain with the varaible resistor "BIAS".

 

TRANSISTORS

The 2N7000 is a common replacement for BS170, however the pinout is a 180 degrees turn. Mount the transistors on the PCB as follows.

 

GENERAL DESCRIPTION OF COMPONENTS

Resistors

The resistors should be ¼ Watt metal type. You can either use a multimeter or the color bands to obtain their values. Resistors do not have polarity, you can place them in any direction.

Electrolytic capacitors

Electrolytic capacitors have their value printed on them. The negative polarity pin is indicated by a white strip along the can. They also have a longer leg indicating the positive pin. The maximum voltage rating never can be exceeded, make sure you are using at least double voltage rating than your power supply. For example, if you are using a 9V power supply, use a electrolytic capacitor with at least 18V maximum voltage rating.

Polyester capacitors

The polyester capacitors have their value marked with three numbers. Read as picofarads (pF), the first two are the 1st and 2nd digits and the third is the multiplier code. These capacitors do not have polarity, you can place them in any direction.

Ceramic capacitors

The ceramic capacitors have their value marked with three numbers. Read as picofarads (pF), the first two are the 1st and 2nd digits and the third is the multiplier code. These capacitors do not have polarity, you can assemble them in any direction.

Tantalum capacitors

Tantalum capacitors have the value printed on them. The polarity is marked for the positive pin. Additionally, the longer leg is the positive and shorter the negative. Assemble the tantalum capacitor according to the positive polarity (+) marked on the PCB.

Diodes

Diodes have their model printed on them. The polarity (cathode) is indicated by the ring near the side. This ring is also marked on the PCB.

Led diodes

Led diodes have polarity, the cathode is indicated as a flat surface on the side of the diode and also it is the shorter led. On the PCB, the cathode is marked as a flat side and anode as a round side.

Transistors

Transistors are three terminals components and their model is printed on them. To indicate the correct orientation, one side of the transistor is flat and the other one is round.

Potentiometers

Potentiometers have their resistance value marked on them. They are marked with A, B or C for logarithmic, linear and reverse logarithmic, respectively.

Trimpots

Trimpots are similar to potentiometers. Their values are printed on them. Use a small screwdriver to adjust them.