Mad Bean Pedals AQB_MOD 2019 User manual

AQB_MOD 2019
FX TYPE: delay modulation
© 2019 madbeanpedals
The AQB_MOD is an add-on board to enable modulation on the Aquaboy (DM-2) project. For the
2019 version, I’ve added an optional LED that displays the modulation rate and an additional resistor
to prevent the depth control from being too extreme.
Controls
• RATE: Sets modulation rate from slow to fast.
• DEPTH: Sets modulation depth from min to max.
• SW: Switches the modulation on and off.
Terms of Use: You are free to use purchased AQB_MOD circuit boards for both DIY and small commercial operations. You may not
offer AQB_MOD PCBs for resale or as part of a “kit” in a commercial fashion. Peer to peer re-sale is ne, though.
Layout &Traces

B.O.M.
B.O.M. Shopping List
Resistors Value QTY Type Rating
R1 220k 1k 2 Carbon / Metal Film 1/8W
R2 220k 2k2 1 Carbon / Metal Film 1/8W
R3 220k 4k7 1 Carbon / Metal Film 1/8W
R4 220k 47k 1 Carbon / Metal Film 1/8W
R5 2k2 220k 5 Carbon / Metal Film 1/8W
R6 1k 10n 1 Film / MLCC 16v min.
R7 1k 22uF 2 Electrolytic 16v min.
R8 220k LED 2 Red, Diffused 3mm
R9 47k 1N4001 1
R10 4k7 9203 1 Photocell
Caps SW 1 SPDT On/On
C1 10n 100kC 1 9mm or 3362p Trimmer
C2 22uF 100kB 1 9mm or 3362p Trimmer
C3 22uF
Diodes
D1 LED
D2 1N4001
LED LED
Photocell
LDR1 9203
IC
IC1 TL062
Switch
SW SPDT
Pots
RATE 100kC
DEPTH 100kB

Parts
You can use either metal shaft 9mm pots or trimmers for the Rate and Depth control. Pots obviously
give you the ability to dial in all kinds of different modulation. But, if you one just one type of modula-
tion (say a slow, subtle modulation on longer delays) then trimmers allow you to just “set and forget”
without having to drill more holes in your enclosure.
9mm metal shaft potentiometers (100kC, 100kB):
http://smallbear-electronics.mybigcommerce.com/alpha-single-gang-9mm-pc-mount/
Bourns 3362p (100k):
https://www.mouser.com/ProductDetail/Bourns/3362P-1-104LF?qs=sGAEpiMZZMvygUB3GLcD7l-
39JMs%2F%2F%2FLOs09gVZSzi2c%3D
https://www.taydaelectronics.com/potentiometer-variable-resistors/cermet-potentiome-
ters/3362p/100k-ohm-trimmer-potentiometer-cermet-1-turn-3362p.html
9203 photocell:
http://smallbear-electronics.mybigcommerce.com/photocells-cds-5mm-diameter/
You can also use some of the cheap Tayda ones:
https://www.taydaelectronics.com/resistors/photoresistors/photo-conductive-cell-resis-
tor-ldr-650nm-radial-ke-10720.html
SPDT Mini (On/On):
http://smallbear-electronics.mybigcommerce.com/spdt-on-on-mountain-10tc410/
SPDT regular size (On/On):
http://smallbear-electronics.mybigcommerce.com/spdt-on-on-short-lever/
Low -prole Electrolytic cap (22uF):
http://smallbear-electronics.mybigcommerce.com/electrolytic-radial-low-prole-16v-1-f-100-f/
• For the LEDs, use 3mm, red diffused for both D1 and LED parts.
• You can use a TL072 instead of the 062 for the IC.
When powered, pin8 of the TL062 should read about 9v, pin4 0v and all other pins will have varying
voltage.
Bend the legs on your photocell and D1 so that the top of the LED points toward the face of the pho-
tocell. You can enclose the LED and Photocell in some heat shrink or tape, but it’s not absolutely
required. However, when testing it outside the enclosure put a towel or something over it to block your
room lights from interacting with the photocell. This will let you know how well the modulation will work
once in the enclosure.
Voltages
Notes

Wiring1
This wiring shows external pots, SPDT switch to turn the modulation on and off and external LED that ashes in time with
the Rate setting. Connect the wire from the SPDT to the “M” pad on the Aquaboy.
Note 1: in this case, connect pads 2 and 1 of the Depth pot on the AQB_MOD PCB as shown.
Note2: you can just leave the external LED off if you do not want the asher.
Experimental:
It’s possible to hook up the Mod board without the switch to turn modulation off. To do so wire the Mod pad on the AQB_
MOD PCB directly to the “M” pad on the Aquaboy PCB. Make R9 220k instead of 47k. When you turn the Depth pot all the
way down, the modulation should go most of the way off. You may still hear a very slight amount, though.
Wiring2
This wiring shows the pots using trimmers. Use this if you only want xed modulation with the delay.
Note1: you can just leave the external LED off if you do not want the asher.

125B Drill Guide
The AQB_MOD board has to t under the Aquaboy PCB. Use some 3m foam tape to securely afx it
to the enclosure. You could also use velcro!

Schematic