aion ZELUS User manual

ZELUS DISTORTION/SUSTAINER 1
PROJECT NAME
ZELUS
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Blackout Effectors Musket Fuzz
Based on the classic Big Muff circuit, this pedal adds a boost to drive the input, a bass blend capacitor,
and a midrange control inside the tone stack.
Distortion / Sustainer, Fuzz 1.0.0 (2019-03-14)
Actual size is 2.3” x 1.86” (main board) and 1.79” x 0.86” (bypass board).
BUILD DIFFICULTY
Easy

ZELUS DISTORTION/SUSTAINER 2
TABLE OF CONTENTS
1Project Overview 8Enclosure Layout
2Introduction & Usage 9Wiring Diagram
3-5 Parts List 10 Licensing
6Schematic 10 Document Revisions
7Drill Template
INTRODUCTION
The Zelus Distortion/Sustainer is adapted from the Blackout Effectors Musket Fuzz version 2, a Big
Muff-based circuit with a few modifications.
First, an input boost has been added to the front of the circuit. This boost is adapted from the Electro-
Harmonix LPB-1 and allows you to drive the input harder than the initial gain stage in a stock Big Muff.
Second, a “Focus” control has been added to blend in a higher capacitor value and allow more bass
through before the clipping stages. With this feature, the Musket is great for bass guitar.
Third, a “Midrange” control has been added to the treble side of the rotation allowing another capacitor
to be gradually blended in parallel with the stock tone capacitor, changing the frequency of that side.
Note that if the tone control is turned all the way to the bass side (counter-clockwise), the Midrange
control will have almost no effect.
With these enhancements, the Musket is a unique and modern take on the Big Muff while retaining the
character of the vintage circuit.
USAGE
The Zelus has the following controls:
• Pre sets the gain of the input stage based on the LPB-1.
• Focus is an input capacitor blend control allowing the bass to be adjusted before the clipping. By
cutting bass at the input, the “tightness” of the effect is improved and it has more clarity.
• Sustain controls the amount of drive or distortion, which also affects the amount of sustain.
• Tone is a the classic Big Muff balance control with a high-pass filter (treble emphasis) on one side
and a low-pass filter (bass emphasis) on the other.
• Mids allows the midrange to be adjusted from scooped to boosted. It is most noticeable on the
treble side of the tone control rotation.
• Volume is the overall output.

ZELUS DISTORTION/SUSTAINER 3
PARTS LIST
This parts list is also available in a spreadsheet format which can be imported directly into Mouser for
easy parts ordering. Mouser doesn’t carry all the parts (most notably potentiometers) so the second tab
lists all the non-Mouser parts as well as sources for each.
View parts list spreadsheet →
PART VALUE TYPE NOTES
R1 1M Metal film resistor, 1/4W
R2 470k Metal film resistor, 1/4W
R3 47k Metal film resistor, 1/4W
R4 10k Metal film resistor, 1/4W
R5 390R Metal film resistor, 1/4W
R6 10k Metal film resistor, 1/4W
R7 10k Metal film resistor, 1/4W
R8 100k Metal film resistor, 1/4W
R9 470k Metal film resistor, 1/4W
R10 12k Metal film resistor, 1/4W
R11 100R Metal film resistor, 1/4W
R12 1k Metal film resistor, 1/4W
R13 10k Metal film resistor, 1/4W
R14 100k Metal film resistor, 1/4W
R15 470k Metal film resistor, 1/4W
R16 12k Metal film resistor, 1/4W
R17 390R Metal film resistor, 1/4W
R18 10k Metal film resistor, 1/4W
R19 100k Metal film resistor, 1/4W
R20 470k Metal film resistor, 1/4W
R21 12k Metal film resistor, 1/4W
R22 390R Metal film resistor, 1/4W
R23 10k Metal film resistor, 1/4W
R24 56k Metal film resistor, 1/4W
R25 470k Metal film resistor, 1/4W
R26 100k Metal film resistor, 1/4W
R27 10k Metal film resistor, 1/4W
R28 2k7 Metal film resistor, 1/4W
R29 47R Metal film resistor, 1/4W
LEDR 4k7 Metal film resistor, 1/4W LED current-limiting resistor. Adjust value to change LED brightness.

ZELUS DISTORTION/SUSTAINER 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
C1 100n Film capacitor, 7.2 x 2.5mm
C2 100n Film capacitor, 7.2 x 2.5mm
C3 100n Film capacitor, 7.2 x 2.5mm
C4 10n Film capacitor, 7.2 x 2.5mm
C5 1uF Film capacitor, 7.2 x 3.5mm
C6 470pF MLCC capacitor, NP0/C0G
C7 100n Film capacitor, 7.2 x 2.5mm
C8 100n Film capacitor, 7.2 x 2.5mm
C9 470pF MLCC capacitor, NP0/C0G
C10 100n Film capacitor, 7.2 x 2.5mm
C11 100n Film capacitor, 7.2 x 2.5mm
C12 470pF MLCC capacitor, NP0/C0G
C13 100n Film capacitor, 7.2 x 2.5mm
C14 3n3 Film capacitor, 7.2 x 2.5mm
C15 47n Film capacitor, 7.2 x 2.5mm
C16 47n Film capacitor, 7.2 x 2.5mm
C17 100n Film capacitor, 7.2 x 2.5mm
C18 100n Film capacitor, 7.2 x 2.5mm
C19 100n MLCC capacitor, X7R Power supply filter capacitor.
C20 100uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
D1 1N5817 Schottky diode, DO-41
D2 1N914 Fast-switching diode, DO-35
D3 1N914 Fast-switching diode, DO-35
D4 1N914 Fast-switching diode, DO-35
D5 1N914 Fast-switching diode, DO-35
Q1 2N5089 BJT transistor, NPN, TO-92
Q2 2N5089 BJT transistor, NPN, TO-92
Q3 2N5089 BJT transistor, NPN, TO-92
Q4 2N5089 BJT transistor, NPN, TO-92
Q5 2N5089 BJT transistor, NPN, TO-92
PRE 100kA 16mm right-angle PCB mount pot
FOCUS 250kB 16mm right-angle PCB mount pot
SUS. 100kA 16mm right-angle PCB mount pot
MIDS 100kA 16mm right-angle PCB mount pot
TONE 250kB 16mm right-angle PCB mount pot

ZELUS DISTORTION/SUSTAINER 5
PARTS LIST, CONT.
PART VALUE TYPE NOTES
VOL. 100kA 16mm right-angle PCB mount pot
IN 1/4" stereo 1/4" phone jack, closed frame Switchcraft 112BX or equivalent.
OUT 1/4" mono 1/4" phone jack, closed frame Switchcraft 111X or equivalent.
DC 2.1mm DC jack, 2.1mm panel mount Mouser 163-4302-E or equivalent.
BATT Battery snap 9V battery snap Optional. Use the soft plastic type—the hard-shell type will not fit.
FSW 3PDT Stomp switch, 3PDT
ENC 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1.

SCHEMATIC
ZELUS DISTORTION/SUSTAINER 6
GND
1M
1N5817
100uF
100kA
100kA
GND
250kB
+9V
100n
VA
GND GND GND GND GNDGND GND GNDGND GNDGND GND
100k
470k
100R 12k
1k
10k
100k
470k
390R 12k
10k
100k
470k
390R 12k
56k
10k
470k100k
10k2k7
100n
470pF
100n
100n
470pF
100n
100n
470pF
100n
3n3
47n
100n
100n
2N5089 2N5089 2N5089
2N5089
100kA
250kB
100kA
VA
VA VA
VA
VA
1N914
1N914
1N914
1N914
47R
47n
470k47k
10k390R
2N5089
GND GND
VA VA
100n
10k
GND
100n
10k
10n1uF
R1
D1
C20
PRE
1
2
3
MIDS
1
2
3
FOCUS
1
2
3
IN
OUT
C19
R8
R9
R11 R10
R12
R13
R14
R15
R17 R16
R18
R19
R20
R22 R21
R24
R23
R25R26
R27R28
C1
C6
C7
C8
C9
C10
C11
C12
C13
C14
C16
C17
C18
Q2 Q3 Q4
Q5
SUSTAIN
1
2
3
TONE
1
2
3
VOLUME
1
2
3
D2
D3
D4
D5
R29
C15
R2R3
R4R5
Q1
C2
R6
C3
R7
C4C5
GND

ZELUS DISTORTION/SUSTAINER 7
DRILL TEMPLATE
Cut out this drill template, fold the edges and tape it to the enclosure. Before drilling, it’s recommended
to first use a center punch for each of the holes to help guide the drill bit.
Ensure that this template is printed at 100% or “Actual Size”. You can double-check this by measuring
the scale on the printed page.
Top jack layout requires the use of closed-frame jacks like the Switchcraft 111X. Open-frame jacks will
not fit in layouts with 5 or more knobs due to the placement of the DC jack in the center.
LED hole drill size assumes the use of a 5mm LED bezel, available from several parts suppliers. Adjust
size accordingly if using something different, such as a 3mm bezel, a plastic bezel, or just a plain LED.
0 1 2
CM
0 1
INCH
x: -0.775, y: +1.71 x: +0.775, y: +1.71
ø9/32” ø9/32”
x: -0.775, y: +0.41
ø9/32”
x: 0, y: +1.71
ø9/32”
x: 0, y: +0.41
ø9/32”
x: +0.775, y: +0.41
ø9/32”
x: 0, y: -1.20
ø15/32”
x: -0.775, y: -1.20
ø5/16”
CENTER (0,0)
125B
SUSTAINMIDSTONE
PREGAINFOCUSVOLUME
FOOTSWITCHLED
ø3/8” ø1/2”
0.385”
0.625” 0.625”
ø3/8”
OUT DC IN

ZELUS DISTORTION/SUSTAINER 8
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

ZELUS DISTORTION/SUSTAINER 9
WIRING DIAGRAM
125B
IN +VGND N.C. N.C. OUT
PCB
IN
GND +V +V JACK GND JACK
OUTIN
GND GND PCB
OUT
Shown with optional 9V battery. If battery is omitted, both jacks can be mono rather than one being stereo.
Leave the far-right lug of the DC jack unconnected.

ZELUS DISTORTION/SUSTAINER 10
LICENSE & USAGE
No direct support is offered for these projects beyond the provided documentation. It’s assumed
that you have at least some experience building pedals before starting one of these. Replacements and
refunds cannot be offered unless it can be shown that the circuit or documentation are in error.
All of these circuits have been tested in good faith in their base configurations. However, not all the
modifications or variations have necessarily been tested. These are offered only as suggestions based
on the experience and opinions of others.
Projects may be used for commercial endeavors in any quantity unless specifically noted. No
attribution is necessary, though a link back is always greatly appreciated. The only usage restrictions
are that (1) you cannot resell the PCB as part of a kit without prior arrangement, and (2) you cannot
“goop” the circuit, scratch off the screenprint, or otherwise obfuscate the circuit to disguise its source.
(In other words: you don’t have to go out of your way to advertise the fact that you use these PCBs, but
please don’t go out of your way to hide it. The guitar effects industry needs more transparency, not less!)
DOCUMENT REVISIONS
1.0.0 (2019-03-14)
Initial release.