Mad Bean Pedals Dustbunny User manual

Dustbunny
FX TYPE: Fuzz
Based on the Tonebender™
Enclosure Size: 1590A
“Softie” compatibility: none
© 2020 madbeanpedals
Overview
The DustBunny is a simple, negative ground silicon Tonebender fuzz tted for a 1590A enclosure.
Controls
• FUZZ: Fuzz from min to max.
• VOL: Output
Terms of Use: You are free to use purchased Dustbunny circuit boards for both DIY and small commercial operations. You may not
offer Dustbunny PCBs for resale or as part of a “kit” in a commercial fashion. Peer to peer re-sale is ne, though.
Technical assistance for your build(s) is available via the madbeanpedals forum. Please go there rather than emailing me for
assistance on builds. This is because (1) I’m not always available to respond via email in a timely and continuous manner, and (2)
posting technical problems and solutions in the forum creates a record from which other members may benet.

Parts Dustbunny
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Values Dustbunny
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Traces Dustbunny
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B.O.M. Dustbunny
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Resistors Caps Diodes
R1 1M C1 10n D1 1N4001
R2 470k C2 4u7 Transistors
R3 100k C3 100n Q1 - Q3 NPN -Si
R4 2k7 C4 47pF Trimmer
R5 10k C5 4u7 BIAS 25k
R6 100k C6 10n Pots
R7 100k C7 47uF FUZZ 1kC
R8 470R C8 100n VOL 100kA
R9 100R
R10 4k7

Shopping List Dustbunny
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Value QTY Type Rating
100R 1 Metal / Carbon Film 1/4W
470R 1 Metal / Carbon Film 1/4W
2k7 1 Metal / Carbon Film 1/4W
4k7 1 Metal / Carbon Film 1/4W
10k 1 Metal / Carbon Film 1/4W
100k 3 Metal / Carbon Film 1/4W
470k 1 Metal / Carbon Film 1/4W
1M 1 Metal / Carbon Film 1/4W
47pF 1 Ceramic / MLCC 16v min.
10n 2 Film 16v min.
100n 2 Film 16v min.
4u7 2 Electrolytic 16v min.
47uF 1 Electrolytic 16v min.
1N4001 1
Si 3 NPN - low hFE
25k 1 Bourns 3362p
1kC 1 PCB Mount, Metal Shaft 9mm
100kA 1 PCB Mount, Metal Shaft 9mm

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Parts Guide Dustbunny
Low prole Electrolytic caps:
http://smallbear-electronics.mybigcommerce.com/electrolytic-radial-low-prole-16v-1-f-100-f/
9mm PC Mount pots (1kC, 100kA):
http://smallbear-electronics.mybigcommerce.com/alpha-single-gang-9mm-right-angle-pc-mount/
Bourns 3362p (25k):
https://www.mouser.com/ProductDetail/Bourns/3362P-1-253LF?qs=sGAEpiMZZMvygUB3GLcD7vRb
QqL9uMLMqIpepdvyyRc%3D
Bourns 3362p (20k):
https://www.taydaelectronics.com/potentiometer-variable-resistors/cermet-potentiometers/3362p/20k-
ohm-trimmer-potentiometer-cermet-1-turn-3362p.html
Thinline DC Jack:
http://smallbear-electronics.mybigcommerce.com/dc-power-jack-all-plastic-unswitched-2-1-mm/
Enclosed Mono:
http://smallbear-electronics.mybigcommerce.com/1-4-in-mono-enclosed-jack/
http://smallbear-electronics.mybigcommerce.com/1-4-in-mono-enclosed-switchcraft-111x/
Lumberg Mono:
http://smallbear-electronics.mybigcommerce.com/lumberg-1-4-compact-shrouded-mono-jack/

Notes Dustbunny
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• There are a variety of NPN silicon transistors that will work in this build. For mine I did the
following - Q1: BC108, Q2, Q3: BC207B (140hFE and 160hFE, resp.) You could use all
BC108/109 or nd a cool mojo mix. Smallbear has plenty to offer for Tonebender types. Generally
smaller gain buckets are better (300 hFE and below).
• Each transistor has a multi-pin layout so if you have straight pin, triangle pin, CBE, EBC, variations
in your transistors they will mount easily. The middle row of three pads are for the base pins of the
transistors.
• C4 is optional. A small cap between collector and base of Q3 can shave off a little hiss or
excessive highs, if desired. Suggest you socket it or just insert the 47pF loose in the pads to see
if you like what it does. You can use higher or lower values - I nd 47pF to be a good start without
removing too much high frequency.
• I’ve used 100n for C6 in previous Tonebender builders. It will add a little more bass. In this build I
stuck with 10n and liked the balance just ne.
• Set the bias of the Q3 collector using your multimeter by turning the trimmer until you read about
4.5v on the “TP” (test point) pad.
MODS
• This version can get very compressed at the highest fuzz setting. Personally, I like this a lot
because there is a very good range of less compressed fuzz tones on lower settings. However,
you can mitigate the compression somewhat by lowering the value of R7. The caveat is the lower
the value of R7 the more C4 starts to act like a (unwanted) lter. So, you may have to remove C4
in that case, or lower it to something like 10pF.
• C1 is probably a good place to start if you want have more high end or want the effect to be
brighter when rolling down the guitar knob. Smaller values will bring some highs back, but don’t go
too far: you might start to pick up radio or get unwanted noise!

Wiring Diagram Dustbunny
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1590A Drill Guide Dustbunny
Note: Drill Guides are approximate and may require tweaking depending on the types of jacks, switches and pots you use.
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• This template will work for either mono enclosed jacks or the “Lumberg”
style.
• It uses the “Thinline” style DC Jack.
• It also shows the 3PDT02 bypass PCB but this is not required. If you are
wiring straight to a 3PDT you can use the same LED location on the right
side or choose a different spot.

Voltages Dustbunny
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• 9.42vDC One Spot
• Current Draw: ~ 2mA
Q1 DC Q2 DC Q3 DC
C7.3 C1.3 C4.6
B1.04 B0.57 B1.35
E0.52 E 0 E 0.72

Build Pic Dustbunny
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Schematic Dustbunny
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