Mad Bean Pedals 3PRR User manual

3PRR
FX TYPE: Utility
© 2015 madbeanpedals
1.815”W x 1.11”H
2015 change-log: Removed 10R current limiting resistor.
This PCB is designed for the typical BLUE 3PDT footswitch. Other
footswitches may or may not fit into the pad spacing allotted.
Terms of Use: You are free to use purchased 3PRR circuit boards for both DIY and
small commercial operations. You may not offer 3PRR boards for resale or as part of a
“kit” in a commercial fashion. Peer to peer re-sale is, of course, okay.

2
V
alue QTY Type Rating
R1 4k7 4k7 1 Carbon / Metal Film 1/4W
100n 1 Film / MLCC 25v
C1 47uF 10uF 5 Electrolytic 25v
C2 100n 47uF 1 Electrolytic 25v
C3 10uF 1N5817 3
C4 10uF Zene
r
1 9.1/12/15v 1W
C5 10uF LM78L15 1 T0-92
C6 10uF Charge Pump 1 *see notes
C7 10uF LED 1 3mm or 5mm
3PDT 1 Solder Lug Footswitch
D1 1N5817
D2 Zener
D3 1N5817
D4 1N5817
LED 3MM/5MM
REG LM78L15
IC1 Charge Pump
BYP 3PDT
IC
Switch
Resistors
Caps
Diodes
Regulator

1590B
4.43”W x 6.47”H
This is the top down view looking at the front face of the 1590B enclosure.

4
The 3PRR is a combination of two utility circuits onto a single PCB: a charge pump / voltage inverter
and bypass switcher. The switching mechanism is true bypass with effect input grounded, and the
charge pump section can provide + or – 9v, +18v (unregulated) and/or +15v (or +12v) regulated. All
outputs can be used simultaneously, if needed, so long as the circuit load does not exceed the
current supply available through the charge pump. This ranges from 20mA-100mA depending on the
charge pump used.
Building tips:
The 3PDT switch and components are mounted on the same side of the PCB (the one with the
component silk screen). The entire assembly is flipped over to mount in the enclosure.
The 9v output is a courtesy output. This can be used if you are building two effects in a larger
enclosure that have different power requirements. Example: a boost that uses 18v and a compressor
that uses 9v. In this case, the 9v pad and G pad would be wired to the compressor. The 18v pad and
the other G pad would be wired to the boost. You should be able to combine positive and negative
ground effects, too. Example: a fuzz that uses -9v and a boost that uses +9v.
You can use any of the following charge pumps: MAX1044CPA, TC1044SCPA, ICL7660SCPA, and
the LT1054. There are two small pads connected to pins 1 and 8 of IC1. These pads must be
jumpered for all the charge pumps EXCEPT the LT1054. Do not jumper the pads for the LT1054.
Special note: These pads were masked over by the manufacturer; they are still solder-able
since they are plated through. Just heat up the jumper and let your solder flow into both pads.
This wiring diagram shows what you will see inside the enclosure.

Charge Pumps:
Type Suffix Connect Pads? Max Input Voltage Max Current Zener Diode (D2)
LT1054 - NO 16v 100mA 15v
ICL7660 SCPA YES 12v 45mA 12v
MAX1044 CPA YES 10v 20mA 9.1v
TC1044 SCPA YES 12v 20mA 12v
Type: These are the four most common charge pumps used in guitar effects. However, you should be
able to use any pin compatible charge pump so long as it will accept a 9v input.
Suffix: When ordering parts, make sure you get the ones with these exact suffix. The ICL and TC
brands have both “CPA” and “SCPA” types. You need the “SCPA” type. The MAX one only has the
CPA, but that is the correct one to use for the Road Rage. The LT1054 does not have the CPA or
SCPA category.
The two pads under IC1 must be connected according to the list above. Failure to connect the pads
correctly will result in an audible whine in your audio path. The LT1054 is the only one that does NOT
need the pads connected.
Max Voltage: This is the maximum input voltage the charge pump can accept. Note that when you
use higher input voltages, your outputs will scale accordingly; a 12v in means 24v out instead of 18v.
The 15v output on the RR PCB will still be 15v since that is determined by the regulator.
Max Current: This is very important. This is the maximum amount of current the charge pump can
supply. So, why not use the LT1054 for everything since it has the most current output? Because it is
more expensive. If you are using the Road Rage to run a dirt pedal at 18v, one of the other charge
pumps will suffice 99% of the time since dirt pedals tend to draw low current. However, some effects
(like an analog delay or Univibe) will have higher current consumption. In those cases, the LT1054 is
necessary.
Zener Diode: This diode will protect your IC from an over-voltage supply. This is optional (the 3PRR
work without it) but if you need to protect the circuit from using a wrong power supply, then use this
list to determine what value Zener to use.
Regulators:
The Road Rage is laid out for a TO-92 style regulator. This should suffice in most cases since most
charge pumps tap out at a maximum of 100mA. A TO-220 style regulator will not fit standing up due
to the extra height of the tab on top. You may be able to mount a TO-220 on the bottom of the board
by bending the mounting pins at right angles, but I have not tried this. Keep in mind that the 220
pinout is also the opposite of what’s on the 3PRR PCB.

6
How to use the Road Rage:
I need -9v output to power a fuzz circuit
Solder D1, D2, C1, C2, C5 and C6 to the PCB. Omit D3, D4, C4, C7, and REG . Connect your DC
jack to the “DC” pads and take your output from the -9/G pins (-9v and ground). BTW: ground is
ground. No matter if you are using a positive or negative ground circuit always connect ground from
the Road Rage to the ground on your circuit. In the case of a fuzz, we just connect -9 to the -9v
supply pad on the fuzz circuit board. It is that simple.
I need +18v output for my overdrive pedal (or whatever)
Solder everything except C5, C6, C7, and REG to the Road Rage PCB. Connect your DC jack to the
“DC” pads and take the output from +18/G. Jumper the two C6 pads to connect pin5 of IC1 to ground.
I need +15v output for my overdrive pedals (or whatever)
Solder everything except C5 and C6. Connect your DC jack to the “DC” pads and take the output
from +15/G. Jumper the two C6 pads to connect pin5 of IC1 to ground.
I need all the voltage outputs to use a power supply for my breadboard or really weird effect pedal
Solder everything. Connect all the outputs.
07.27 Update: The pads for the boost option on pg.4 have been increased in size and labeled for
easier soldering. This is the only change.