aion Aurora Deluxe User manual

AURORA DELUXE COMPRESSOR 1
PROJECT NAME
AURORA DELUXE
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Keeley Compressor Plus
An expanded version of the classic Ross/Dyna Compressor with an added clean blend, treble control,
and output buffer.
Compressor with clean blend 1.0.0 (2023-11-24)
BUILD DIFFICULTY
Intermediate
Actual size is 2.3” x 2.42” (main board) and 1.78” x 0.86” (bypass board).

AURORA DELUXE COMPRESSOR 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 Aurora Deluxe Compressor is based on the Keeley Compressor Plus, an updated version of their
world-famous compressor. It was first released in 2017 and was traced by Aion FX in 2023.
Internally, it’s a Ross/Dyna Comp as with the original compressor circuit. A clean blend has been added,
as well as a subtle treble control that boosts very high frequencies and adds a touch of brightness or
presence. To make room for the two new knobs, they omitted the Clipping knob (an input attenuator)
as well as converting the Attack knob to a two-position switch. It’s also been converted to use the
LM13700, a current-production version of the obsolete CA3080.
The Compressor Plus fully replaced the previous Compressor. In fact, the standard version artwork
omits the “Plus” and just labels it the “Keeley Compressor” in the same font as the original, though the
product description does call it the Compressor Plus.
The Aurora Deluxe is a direct adaptation based on our trace of the Compressor Plus. The only difference
is that we added a third position to the Attack (Release) switch that simulates the 12:00 position
on the original control. We also combined two series capacitors that were clearly left over from the
prototyping process.
USAGE
The Aurora Deluxe has four knobs and one toggle switch:
• Sustain controls the amount of compression. As you turn it up, it increases the sustain but also the
noise level. If you keep it down below 12:00, it acts more like a limiter.
• Blend sets the ratio of clean to effected signal.
• Tone boosts the high-end response of the effect, with a corner frequency of 2.3kHz at maximum.
• Level is the overall output volume of the effect.
• Attack (toggle) allows you to set the amount of time after the input signal falls below the threshold
before the compressor “resets” and is ready to compress again. It’s technically a “Release” control,
but “Attack” is a more common way of describing it in commercial circuits including the Boss CS-2.

AURORA DELUXE COMPRESSOR 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—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 10k Metal film resistor, 1/4W
R2 470k Metal film resistor, 1/4W
R3 470k Metal film resistor, 1/4W
R4 10k Metal film resistor, 1/4W
R5 10k Metal film resistor, 1/4W
R6 1M Metal film resistor, 1/4W
R7 1k Metal film resistor, 1/4W
R8 1k Metal film resistor, 1/4W
R9 220k Metal film resistor, 1/4W
R10 220k Metal film resistor, 1/4W
R11 1M Metal film resistor, 1/4W
R12 15k Metal film resistor, 1/4W
R13 150k Metal film resistor, 1/4W
R14 27k Metal film resistor, 1/4W
R15 10k Metal film resistor, 1/4W
R16 10k Metal film resistor, 1/4W
R17 1M Metal film resistor, 1/4W
R18 39k Metal film resistor, 1/4W
R19 150k Metal film resistor, 1/4W
R20 10k Metal film resistor, 1/4W
R21 1M Metal film resistor, 1/4W
R22 10k Metal film resistor, 1/4W
R23 47k Metal film resistor, 1/4W
R24 10k Metal film resistor, 1/4W
R25 47k Metal film resistor, 1/4W
R26 12k Metal film resistor, 1/4W
R27 15k Metal film resistor, 1/4W
R28 15k Metal film resistor, 1/4W
R29 15k Metal film resistor, 1/4W
R30 15k Metal film resistor, 1/4W
R31 10k Metal film resistor, 1/4W
R32 1M Metal film resistor, 1/4W

AURORA DELUXE COMPRESSOR 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
R33 1M Metal film resistor, 1/4W
R34 27k Metal film resistor, 1/4W
R35 10k Metal film resistor, 1/4W
R36 100k Metal film resistor, 1/4W
R37 10k Metal film resistor, 1/4W
R38 10k Metal film resistor, 1/4W
R39 390R Metal film resistor, 1/4W
R40 56k Metal film resistor, 1/4W
R41 27k Metal film resistor, 1/4W
R42 10k Metal film resistor, 1/4W
R43 10k Metal film resistor, 1/4W
R44 47R Metal film resistor, 1/4W Power supply filter resistor.
RPD 1M Metal film resistor, 1/4W Input pulldown resistor.
LEDR 10k Metal film resistor, 1/4W LED current-limiting resistor. Adjust value to change LED brightness.
C1 150pF MLCC capacitor, NP0/C0G
C2 22n Film capacitor, 7.2 x 2.5mm
C3 1uF Electrolytic capacitor, 4mm
C4 1uF Electrolytic capacitor, 4mm
C5 1uF Film capacitor, 7.2 x 3.5mm
C6 1uF Electrolytic capacitor, 4mm
C7 10n Film capacitor, 7.2 x 2.5mm
C8 1uF Electrolytic capacitor, 4mm
C9 1n Film capacitor, 7.2 x 2.5mm
C10 10n Film capacitor, 7.2 x 2.5mm
C11 10uF Electrolytic capacitor, 5mm
C12 10n Film capacitor, 7.2 x 2.5mm
C13 47n Film capacitor, 7.2 x 2.5mm
C14 6n8 Film capacitor, 7.2 x 2.5mm
C15 47pF MLCC capacitor, NP0/C0G
C16 22n Film capacitor, 7.2 x 2.5mm
C17 47n Film capacitor, 7.2 x 2.5mm
C18 220uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C19 47uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C20 47uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C21 100n MLCC capacitor, X7R Power supply filter capacitor.
D1 1N5817 Schottky diode, DO-41
D2 1N914 Fast-switching diode, DO-35

AURORA DELUXE COMPRESSOR 5
PARTS LIST, CONT.
PART VALUE TYPE NOTES
D3 1N914 Fast-switching diode, DO-35
Q1 2N5088 BJT transistor, NPN, TO-92
Original uses MMBT6429 (SMD). 2N5088 is a close
substitute. Can also use BC549C, but these will need to be
rotated 180 degrees from the silkscreen.
Q2 2N5088 BJT transistor, NPN, TO-92
Q3 2N5088 BJT transistor, NPN, TO-92
Q4 2N5088 BJT transistor, NPN, TO-92
Q5 2N5088 BJT transistor, NPN, TO-92
IC1 LM13700N Transconductance amplifier, dual, DIP16 Can also use NE5517N.
IC1-S DIP-16 socket IC socket, DIP-16 Can also use two DIP-8 sockets.
IC2 RC4558P Operational amplifier, dual, DIP8
IC2-S DIP-8 socket IC socket, DIP-8
IC3 RC4558P Operational amplifier, dual, DIP8
IC3-S DIP-8 socket IC socket, DIP-8
SUSTAIN 500KC 16mm right-angle PCB mount pot Reverse audio (reverse log or antilog) taper.
TONE 100kB 16mm right-angle PCB mount pot Linear taper.
BLEND 10kB 16mm right-angle PCB mount pot Linear taper.
LEVEL 100kA 16mm right-angle PCB mount pot Audio (log) taper.
ATTACK SPDT on-off-on Toggle switch, SPDT center off
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.

AURORA DELUXE COMPRESSOR 6
BUILD NOTES
Transistor substitutions
The original Compressor Plus uses MMBT6429 transistors, which do not have a current-production
through-hole equivalent. They are medium-gain low-noise transistors that are very close in specification
to the 2N5088 or BC549C.
The Aurora Deluxe PCB uses the USA E-B-C convention for Q1-Q5, so the 2N5088 will be a direct fit.
The BC549C or other European C-B-E convention transistors will need to be rotated 180 degrees from
the PCB silkscreen.
IC substitutions
The very first version of the Compressor Plus used NE5532 for IC2 and IC3, the two dual op-amps.
They soon switched to RC4558P, which are still used in current models. The NE5532 has lower noise
and a better slew rate, but significantly higher current draw. The RC4558P is perfectly adequate for the
application and is recommended to use in this project, but you can use either type, or whatever else you
want such as a the TL072 or OPA2134.
The LM13700N was obsoleted recently in through-hole format, but is still readily available, including
from major distributors like Mouser. The NE5517N is a second-source substitute that will perform
identically, and is available from Aion FX.

SCHEMATIC
AURORA DELUXE COMPRESSOR 7
OUT
IN
1N5817
+9V
100n
GND
1M
10k
470k
10k
1M
220k 220k
10k
1M
15k
150k
10k10k
1M 1M
470k
27k
150pF
22n
1uF
10n
10n 10n
47n
2N5088
2N5088
2N5088 2N5088
2N5088
GND
1uF
1uF
1uF
1uF
GND
GND
1N914
1N914
500KC
100kA
1k 1k
GND
GND
GND
GND GND
GND GND GND GND GND GND GND GND GND
GND
LM13700N
LM13700N
LM13700N
LM13700N
GND
VA
VB
VB
VA
VA
VA VA
10k
10uF
150k 10k
56k27k
GND
GND GND
VA
VB
47uF
220uF
10k10k
GND
VC
47uF
GND
1n
39k
VA
47k
6n8
100kB
10k
RC4558P
RC4558P
RC4558P
RC4558P
47k
47pF
GND
VA
VA
GND
VC
12k
15k
10kB
VC
15k
15k
100k
VC
10k
10k
VC
390R
15k
22n
10k
1M1M
GND
VA
27k 10k
VC
47n
47R
D1
C21
RPD
R1
R2
R5
R6
R9 R10
R4
R11
R12
R13
R15R16
R17 R21
R3
R14
C1
C2
C5
C7
C10
C12
C13
Q1
Q2
Q3 Q4
Q5
C3
C6
C4
C8
D2 D3
SUSTAIN
1
2
3
LEVEL
1
2
3
R7 R8 IC1B
14
13
12
16
15
IC1_BUF1
V+
7
8
IC1A
3
4
5
1
2IC1_BUF2
V+
10
9
116
R22
C11
R19 R20
R40R41
C19
C18
R42R43
C20
C9
2
3
1
ATTACK
R18
R23
C14
1
2
3
TONE
R24
2
3
1
IC2A
2
3
1
IC3A
6
5
7
IC2B
6
5
7
IC3B
R25
C15
84
84
R26
R27
BLEND
1
2
3
R28
R29
R36
R37
R38
R39
R30
C16
R31
R32R33
R34 R35
C17
R44
GND

AURORA DELUXE COMPRESSOR 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 assumes the use of closed-frame jacks like the Switchcraft 111X. If you’d rather use
open-frame jacks, please refer to the Open-Frame Jack Drill Template for the top side.
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.
ø3/8” ø1/2”
0.385”
0.625” 0.625”
x: 0, y: -1.775
ø15/32”
x: -0.775, y: -1.775
ø5/16”
ø3/8”
125B
OUT
FOOTSWITCHLED
DC IN
CENTER (0,0)
TONE BLEND
SUSTAIN LEVEL
ATTACK
x: 0, y: +1.06
ø1/4”
x: -0.65, y: +1.71 x: 0.65, y: +1.71
ø9/32” ø9/32”
x: -0.65, y: +0.41
ø9/32”
x: 0.65, y: +0.41
ø9/32”
0 1 2
CM
0 1
INCH

AURORA DELUXE COMPRESSOR 9
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

AURORA DELUXE COMPRESSOR 10
WIRING DIAGRAM
125B
IN +VGND NC NC OUT
PCB
IN
GND +V +V JACK GND JACK
OUTIN
GND GND PCB
OUT

AURORA DELUXE COMPRESSOR 11
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 cannotbe 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 (2023-11-24)
Initial release.