aion TEMPEST User manual

TEMPEST AMP DISTORTION 1
PROJECT NAME
TEMPEST
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Friedman®BE-OD / Dirty Shirley
A pedal recreation of the Friedman®BE-100 and Dirty Shirley amplifiers.
Amp-Like Distortion 1.0.1 (2019-03-08)
BUILD DIFFICULTY
Intermediate
Actual size is 2.3” x 2.42” (main board) and 1.78” x 0.86” (bypass board).

TEMPEST AMP DISTORTION 2
TABLE OF CONTENTS
1Project Overview 8Drill Template
2Introduction & Usage 9Enclosure Layout
3-5 Parts List 10 Wiring Diagram
6Build Notes 11 Licensing
7Schematic 11 Document Revisions
INTRODUCTION
The Tempest Amp Distortion is a combination of the Friedman®BE-OD and Dirty Shirley pedals, two
very similar circuits that were designed to emulate high-gain amplifiers.
It’s not a true amp emulator of the sort that replace the tubes with JFETs, as Runoffgroove is famous
for. Instead, it’s fully driven by op-amps, but very carefully designed in a way to mimic the response and
character of a Friedman amplifier. And by all accounts it has succeeded, quickly becoming one of the
most revered “amp in a box” pedals on the scene today.
The original Friedman BE-OD is missing a midrange control, while the Dirty Shirley has a midrange
control but converts the Tight knob into a toggle switch. The Tempest project combines these together,
preserving the midrange control while also leaving the Tight control as a knob instead of a switch, for a
total of seven knobs.
USAGE
The Tempest has the following controls, which correspond to the same controls on the BE-100 or Dirty
Shirley amplifiers.
• Gain is the overall distortion or drive level of the effect.
• Volume controls the overall output of the effect.
• Presence is low-pass filter that sets the high-end cutoff frequency between 1.3 KHz and 7.2 KHz.
• Tight is a high-pass filter that sets the low-end cutoff frequency between 150Hz and 3.3 KHz near
the beginning of the circuit.
• Bass, Mid and Treble form a 3-band EQ. These controls are all at different stages in the circuit, so
they are not interactive with each other in the same way that a Marshall or Fender-style tonestack
would be.

TEMPEST AMP DISTORTION 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 330k Metal film resistor, 1/4W
R2 10k Metal film resistor, 1/4W
R3 22k Metal film resistor, 1/4W
R4 39k Metal film resistor, 1/4W
R5 4k7 Metal film resistor, 1/4W
R6 10k Metal film resistor, 1/4W
R7 22k Metal film resistor, 1/4W
R8 22k Metal film resistor, 1/4W
R9 22k Metal film resistor, 1/4W
R10 220k Metal film resistor, 1/4W
R11 22k Metal film resistor, 1/4W
R12 27k Metal film resistor, 1/4W
R13 10k Metal film resistor, 1/4W
R14 2k2 Metal film resistor, 1/4W
R15 33k Metal film resistor, 1/4W
R16 33k Metal film resistor, 1/4W
R17 2k2 Metal film resistor, 1/4W
R18 470k Metal film resistor, 1/4W
R19 2k2 Metal film resistor, 1/4W
R20 2k2 Metal film resistor, 1/4W
R21 22k Metal film resistor, 1/4W
R22 100k Metal film resistor, 1/4W
R23 2k2 Metal film resistor, 1/4W
R24 10R Metal film resistor, 1/4W Power supply filtering resistor.
R25 20k Metal film resistor, 1/4W
R26 22k Metal film resistor, 1/4W
R27 2k2 Metal film resistor, 1/4W
R28 20k Metal film resistor, 1/4W
R29 22k Metal film resistor, 1/4W
R30 2k2 Metal film resistor, 1/4W

TEMPEST AMP DISTORTION 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
RPD 2M2 Metal film resistor, 1/4W Input pulldown resistor. Can be as low as 1M.
LEDR 4k7 Metal film resistor, 1/4W LED current-limiting resistor. Adjust value to change LED brightness.
C1 22n Film capacitor, 7.2 x 2.5mm
C2 47pF MLCC capacitor, NP0/C0G
C3 10n Film capacitor, 7.2 x 2.5mm
C4 1n Film capacitor, 7.2 x 2.5mm
C5 47pF MLCC capacitor, NP0/C0G
C6 100n Film capacitor, 7.2 x 2.5mm
C7 47n Film capacitor, 7.2 x 2.5mm
C8 120pF MLCC capacitor, NP0/C0G
C9 220pF MLCC capacitor, NP0/C0G
C10 10n Film capacitor, 7.2 x 2.5mm
C11 4n7 Film capacitor, 7.2 x 2.5mm
C12 22n Film capacitor, 7.2 x 2.5mm
C13 220n Film capacitor, 7.2 x 2.5mm
C14 2n2 Film capacitor, 7.2 x 2.5mm
C15 10n Film capacitor, 7.2 x 2.5mm
C16 220n Film capacitor, 7.2 x 2.5mm
C17 100uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C18 100n MLCC capacitor, X7R Power supply filter capacitor.
C19 22uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C20 100n MLCC capacitor, X7R Reference voltage filter capacitor.
C21 22uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C22 100n MLCC capacitor, X7R Reference voltage filter capacitor.
D1 1N5817 Schottky diode, DO-41
D2 3mm LED, 3mm, red diffused
D3 3mm LED, 3mm, red diffused
D4 1N914 Fast-switching diode, DO-35
D5 1N914 Fast-switching diode, DO-35
D6 1N914 Fast-switching diode, DO-35
D7 1N914 Fast-switching diode, DO-35
D8 3mm LED, 3mm, red diffused
D9 3mm LED, 3mm, red diffused
TRIM 100k trimmer Trimmer, 10%, 1/4” Adjusts the overall gain range of the effect.

TEMPEST AMP DISTORTION 5
PARTS LIST, CONT.
PART VALUE TYPE NOTES
IC1 TL072 Operational amplifier, DIP8
IC2 TL072 Operational amplifier, DIP8
IC3 TL072 Operational amplifier, DIP8
IC4 TL072 Operational amplifier, DIP8
IC1-S DIP-8 socket IC socket, DIP-8
IC2-S DIP-8 socket IC socket, DIP-8
IC3-S DIP-8 socket IC socket, DIP-8
IC4-S DIP-8 socket IC socket, DIP-8
BASS 100kC 16mm right-angle PCB mount pot
TREBLE 100kB 16mm right-angle PCB mount pot
MID 100kC 16mm right-angle PCB mount pot
PRES. 10kC 16mm right-angle PCB mount pot
TIGHT 100kC 16mm right-angle PCB mount pot
GAIN 1MA 16mm right-angle PCB mount pot
VOL. 50kA 16mm right-angle PCB mount pot
LED 5mm LED, 5mm, red diffused
IN 1/4" mono 1/4" phone jack, closed frame Switchcraft 111X 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.
FSW 3PDT Stomp switch, 3PDT
ENC 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1.

TEMPEST AMP DISTORTION 6
BUILD NOTES
Circuit architecture
This circuit has several cascaded gain & clipping stages, but overall it’s pretty linear without a lot of
interaction between the sections. Here is a block diagram of how the circuit is arranged:
Setting the gain trimmer
The circuit has an on-board internal trimmer to adjust the overall gain range of the circuit. This is
different from the external gain control. As you can see in the block diagram above, this gain stage
comes after the two soft-clipping stages, but before the final hard-clipping stage. It’s a simple op-amp
stage that boosts or cuts the signal going into the hard clipping stage, so it primarily impacts the amount
of hard clipping.
At its stock setting of 12:00, the pedal could be considered a medium-gain drive. By turning it up, you
can shift it into the mid-to-high gain range.
Conversely, by turning it down, you can have better control over the low gain range, but the pedal will
lack the high-gain tones that you might expect from it.
INPUT TIGHT
(LOW CUT)
PRESENCE
(HIGH CUT)
VOLUME
GAIN /
SOFT CLIP
HARD CLIP
MID
GAIN
TRIMMER
BASS
SOFT CLIP
TREBLE
OUTPUT

SCHEMATIC
TEMPEST AMP DISTORTION 7
GND
1M
100uF
100kC
10kC
GND
100kC
100kB
100kC
50kA
+9V
22n
330k
1N5817
10k
47pF
10R
GND
100n
1MA
TL072P
TL072P
TL072P
TL072P
22k
39k
GND
VA
VA
10n
4k7
VRVR
VR
10k
1n
GND
47pF
22k
VA
GND
22k
100n
GND
LED
LED
47n
22k TL072P
VB
220k
22k
VA
GND
120pF
1N914 1N914
1N9141N914
27k TL072P
10k
220pF
100kB
2k2
10n
GND
20k
2k2
22k
GND GND GND
100n
VR
20k
2k2
22k
GND GND GND
100n
VB
VB
VB
4n7
GND
TL072P
22n
33k 33k
220n
GND
2k2
VB
470k
VB
2k2
GND
VA
TL072P
2n2
2k2
22k
10n
GND
220n
100k
2k2
GND
22uF22uF
RPD
C17
TIGHT
1
2
3
PRESENCE
1
2
3
MID
1
2
3
TREBLE
1
2
3
BASS
1
2
3
VOLUME
1
2
3
IN
OUT
C1
R1
D1
R2
C2
R24
C18
GAIN
1
2
3
IC1A
2
3
1
IC1B
6
5
7
IC2A
2
3
1
IC2B
6
5
7
R3
R4
84
C3
R5
R6
C4
C5
R7
84
R8
C6 D2
D3
C7
R9
IC3A
2
3
1
R10
R11
84
C8
D4 D5
D6D7
R12
IC3B
6
5
7
R13
C9
TRIM
1
2
3
R14
C10
D8
D9
R25
R27
R26
C20
R28
R30
R29
C22
C11
IC4A
2
3
1
C12
R15 R16
C13
R17
R18
R19
84
IC4B
6
5
7
C14
R20
R21
C15
C16
R22
R23
C21C19
GND

TEMPEST AMP DISTORTION 8
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.
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
ø3/8” ø1/2”
0.385”
0.625” 0.625”
x: -0.775, y: +1.71 x: +0.775, y: +1.71
ø9/32” ø9/32”
x: 0, y: +0.535
ø9/32”
x: +0.775, y: +0.535
ø9/32”
x: 0, y: -1.775
ø15/32”
x: -0.775, y: -1.775
ø5/16”
CENTER (0,0)
ø3/8”
125B
OUT
VOLUME
x: 0, y: +1.71
ø9/32”
PRESENCE
x: 0, y: -0.64
ø9/32”
TIGHT
GAIN
MID
x: -0.775, y: +0.535
ø9/32”
TREBLE BASS
FOOTSWITCHLED
DC IN

TEMPEST AMP DISTORTION 9
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

TEMPEST AMP DISTORTION 10
WIRING DIAGRAM
125B
IN +VGND NC NC OUT
PCB
IN
GND +V +V JACK GND JACK
OUTIN
GND GND PCB
OUT