aion PROCYON User manual

PROCYON NATURAL OVERDRIVE 1
PROJECT NAME
PROCYON
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
BJFe Honey Bee Overdrive
A workalike of one of the original hand-made boutique pedals, originally modeled after vintage Supro
amps and noted for its dynamic low-gain tone.
Overdrive 1.0.0 (2018-08-22)
BUILD DIFFICULTY
Beginner
Actual size is 2.3” x 1.86” (main board) and 2.3” x 0.86” (bypass board).

PROCYON NATURAL OVERDRIVE 2
TABLE OF CONTENTS
1Project Overview 7Enclosure Layout
2Introduction & Usage 8Wiring Diagram
3-4 Parts List 9Licensing
5Schematic 9Document Revisions
6Drill Template
INTRODUCTION
The Procyon Natural Overdrive is a clone of the BJFe Honey Bee Overdrive, a circuit first released in
2002 that is credited for starting the “low gain overdrive” trend.
The circuit itself is a rather unique overdrive design, incorporating both soft and hard clipping and
utilizing frequency-dependent negative feedback from different points in the circuit, for a result that is
often called “amplike” in tone.
These pedals were handmade in Sweden and were extremely expensive ($300-400 USD), and so in 2011
an agreement was made with BearFoot FX to produce them in the USA for a more reasonable cost.
Bearfoot has also released a number of variants of this basic circuit such as the Model H, Model G,
Honey Beest, Uber Bee, and Sparkling Yellow Overdrive. While each of these circuits are similar, the
Procyon project only supports the standard Honey Bee (both BJFe and BearFoot versions, which have
minor differences).
USAGE
The Procyon has the same control layout as most overdrive or distortion effects:
• Drive controls the gain of the op-amp stage which increases the amount of signal clipping.
• Nature is a very unique tone control, doing two things at once. On one half of the rotation it
affects the amount of bass and changes the gain structure of the circuit. On the other half of the
rotation, it blends in a frequency bypass capacitor on the gain-recovery FET, causing the highs to
be emphasized more. The end result is that you have more bass on one side and more treble on the
other, but the manner of accomplishing this is very different than something like the Big Muff.
• Volume controls the overall output level of the effect.

PROCYON NATURAL OVERDRIVE 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 360k Metal film resistor, 1/4W
R2 15k Metal film resistor, 1/4W
R3 3k Metal film resistor, 1/4W
R4 1k Metal film resistor, 1/4W
R5 1k Metal film resistor, 1/4W
R6 27k Metal film resistor, 1/4W
R7 10k Metal film resistor, 1/4W
R8 47k Metal film resistor, 1/4W
R9 1M Metal film resistor, 1/4W
R10 2k2 Metal film resistor, 1/4W
R11 5k6 Metal film resistor, 1/4W
R12 47k Metal film resistor, 1/4W
R13 51R Metal film resistor, 1/4W
R14 31k6 Metal film resistor, 1/4W
R15 31k6 Metal film resistor, 1/4W
RX1 4k7 Metal film resistor, 1/4W Only in the BearFoot version. Jumper RX1 for a stock BJFe Honey Bee.
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 47n Film capacitor, 7.2 x 2.5mm
C2 100pF MLCC capacitor, NP0/C0G
C3 220n Film capacitor, 7.2 x 2.5mm
C4 2.2uF Film capacitor, 7.2 x 5mm
C5 4n7 Film capacitor, 7.2 x 2.5mm 220n in the BearFoot version.
C6 1uF Film capacitor, 7.2 x 3.5mm
C7 22n Film capacitor, 7.2 x 2.5mm
C8 4n7 Film capacitor, 7.2 x 2.5mm
C9 22n Film capacitor, 7.2 x 2.5mm
C10 4n7 Film capacitor, 7.2 x 2.5mm
C11 1uF Film capacitor, 7.2 x 3.5mm
C12 4n7 Film capacitor, 7.2 x 2.5mm

PROCYON NATURAL OVERDRIVE 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
C13 100uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C14 22uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C15 100n MLCC capacitor, X7R Power supply filter capacitor.
D1 1N5817 Schottky diode, DO-41
D2 5mm LED LED, 5mm, red diffused
D3 5mm LED LED, 5mm, red diffused
D4 1N4007 Rectifier diode, DO-41
D5 1N4007 Rectifier diode, DO-41
Q1 2N5457 JFET, N-channel, TO-92 Substitute. Original uses BF244A.
IC1 CA3130EZ Operational amplifier, DIP8
IC1-S DIP-8 socket IC socket, DIP-8
DRIVE 500kA 16mm right-angle PCB mount pot
VOL 50kB 16mm right-angle PCB mount pot
NATR 50kA 16mm right-angle PCB mount pot
LED 5mm LED, 5mm, red diffused
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
PROCYON NATURAL OVERDRIVE 5
GND
2M2
N5817
100uF
GND
+9V
100n
VA
51R
500kA
50kB
31k6
31k6
22uF
VR
GND GND
50kA
47n
360k
15k
CA3130EZ
GND
VR
100pF
3k
5MM LED
5MM LED
1k
220n
GND
2u2
4n7
GND
1k
1uF
22n
27k
10k
4n7
47k
22n
4n7
1M
2k2
1N4007
1N4007
GND
GND
GND
GND
5k6
1uF
47k
4n7
GND
4k7
2N5457
VA
VA
RPD
D1
C13
IN
OUT
C15
R13
DRIVE
1
2
3
VOLUME
1
2
3
R14
R15
C14
NATURE
1
2
3
C1
R1
R2 5
1
2
3
6
8
74
IC1
C2
R3
D2
D3
R4
C3 C4
C5
R5
C6
C7
R6
R7
C8
R8
C9
C10
R9
R10
D4 D5
R11
C11
R12
C12
RX1
Q1
GND

PROCYON NATURAL OVERDRIVE 6
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.
x: -0.65, y: +1.71 x: 0.65, y: +1.71
ø9/32” ø9/32”
x: 0, y: +0.66
ø9/32”
x: 0, y: -1.20
ø15/32”
x: -0.775, y: -1.20
ø5/16”
CENTER (0,0)
125B
VOLUME DRIVE
NATURE
FOOTSWITCHLED
ø3/8” ø1/2”
0.385”
0.625” 0.625”
ø3/8”
OUT DC IN
0 1 2
CM
0 1
INCH

PROCYON NATURAL OVERDRIVE 7
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

PROCYON NATURAL OVERDRIVE 8
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.

PROCYON NATURAL OVERDRIVE 9
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 (2018-08-22)
Initial release.