aion TITAN User manual

TITAN DYNAMIC DRIVE 1
PROJECT NAME
TITAN
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Fulltone®OCD®
A legendary hard-clipping overdrive pedal that makes almost any rig sound better.
Overdrive / distortion 1.0.0 (2023-03-24)
BUILD DIFFICULTY
Easy
Actual size is 2.3” x 1.86” (main board) and 1.78” x 0.87” (bypass board).
Fulltone®, OCD®and Obsessive Compulsive Drive®are registered trademarks of Fulltone Musical
Products Inc. Any use of these trademarks is for comparative purposes only. Aion FX has no
affiliation with Fulltone Musical Products and this project is not endorsed by them.
IMPORTANT NOTE

TITAN DYNAMIC DRIVE 2
TABLE OF CONTENTS
1Project Overview 8Drill Template
2Introduction & Usage 9Enclosure Layout
3-4 Parts List 10 Wiring Diagram
5-6 Build Notes 11 Licensing
7Schematic 11 Document Revisions
INTRODUCTION
The Titan Dynamic Drive is an adaptation of the legendary Fulltone®OCD®. The Obsessive Compulsive
Drive was first released in 2005, itself a modified version of the Voodoo Labs Overdrive with several
added features and tweaks.
There were seven different official versions of V1 from its initial release until it was replaced by the V2
in 2017. Prior to the release of the “true” V2, these versions were referred to by the gear community as
V1, V2, V3, etc., but they’ve always been labeled V1.1, V1.2, V1.3, etc. inside the enclosure.
The Titan is a fully-overhauled version of our original legacy project. This version omits the on-board
18V charge pump in favor of a simplified layout. 18V mode can easily be added with our 18V Bypass
PCB, which is compatible with this project. It also supports external 18V power like the original.
In place of this, we’ve added several new features, bringing in the most noticeable circuit tweaks from
V1.1 through V1.7 and using DIP switches to make them configurable. The result is a tonal workstation,
allowing you to tailor your own perfect version of the circuit.
We’ve included extensive documentation on the major differences between the versions and the switch
combinations that correspond most closely to each. The default parts list corresponds to v1.7, which is
the version that was in production the longest with around ~75,000 units manufactured.
USAGE
The Titan has the typical controls of a 3-knob overdrive:
• Drive controls the amount of gain pushed into the hard-clipping diodes.
• Tone controls the treble response via a passive filter.
• Volume controls the overall output.
There are also two toggle switches:
• Clipping (toggle switch) selects between soft clipping (overdrive), hard clipping (distortion) and no
clipping (clean boost).
• HP/LP (toggle switch) selects between “high peak” and “low peak” mode, which affects the range
and travel of the tone control. With Tone fully up, it just provides a slight volume boost, no different
than turning up the volume control a bit.
In addition, there are two internal 3-position DIP switches, which are described in detail on page 5.

TITAN DYNAMIC DRIVE 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 18k Metal film resistor, 1/4W
R4 2k2 Metal film resistor, 1/4W
R5 10k Metal film resistor, 1/4W
R6 10k Metal film resistor, 1/4W
R7 150k Metal film resistor, 1/4W
R8 39k Metal film resistor, 1/4W
R9 33k Metal film resistor, 1/4W
R10 22k Metal film resistor, 1/4W
R11 1k Metal film resistor, 1/4W
R12 10k Metal film resistor, 1/4W
R13 10k Metal film resistor, 1/4W
R14 100R Metal film resistor, 1/4W Power supply filter resistor.
RPD 1M Metal film resistor, 1/4W Input pull-down resistor.
LEDR 10k 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 220pF MLCC capacitor, NP0/C0G
C3 68n Film capacitor, 7.2 x 2.5mm
C4 1n Film capacitor, 7.2 x 2.5mm
C5 220pF MLCC capacitor, NP0/C0G
C6 100n Film capacitor, 7.2 x 2.5mm
C7 1uF Film capacitor, 7.2 x 3.5mm
C8 47n Film capacitor, 7.2 x 2.5mm
C9 47n Film capacitor, 7.2 x 2.5mm
C10 47n Film capacitor, 7.2 x 2.5mm
C11 10n Film capacitor, 7.2 x 2.5mm
C12 33n Film capacitor, 7.2 x 2.5mm
C13 47uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C14 100uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C15 100n MLCC capacitor, X7R Power supply filter capacitor.

TITAN DYNAMIC DRIVE 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
D1 1N5817 Schottky diode, DO-41
D2 Ge Germanium diode, DO-7 Any germanium diode should work about the same in this circuit, so use
whatever you can find. See build notes for precautions about polarity.
D3 Ge Germanium diode, DO-7
D4 3mm LED LED, 3mm, red diffused Can also use 5mm.
D5 3mm LED LED, 3mm, red diffused Can also use 5mm.
Q1 2N7000 MOSFET, N-channel, TO-92 Can also use BS170 (rotate 180 degrees).
Q2 2N7000 MOSFET, N-channel, TO-92 Can also use BS170 (rotate 180 degrees).
IC1 TL082 Operational amplifier, DIP8
IC1-S DIP-8 socket IC socket, DIP-8
SW1 3-pos. DIP DIP switch, 3-position See build notes for switch settings.
SW2 3-pos. DIP DIP switch, 3-position See build notes for switch settings.
DRIVE 1MA 16mm right-angle PCB mount pot
TONE 10kB 16mm right-angle PCB mount pot
VOL. 100kB 16mm right-angle PCB mount pot
CLIP SPDT on-on Toggle switch, SPDT on-on
HP/LP SPDT on-on Toggle switch, SPDT on-on
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.
FSW 3PDT Stomp switch, 3PDT
BATT. 9V 9V battery snap Soft vinyl type. The hard-shell type will not fit.
ENC 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1.

TITAN DYNAMIC DRIVE 5
BUILD NOTES
DIP switch settings
The OCD V1 had seven major versions, and many of the circuit changes across versions make a
noticeable difference to the tone. In this updated version of the Titan, we added DIP switches to make
several of these changes selectable so you can capture the main sonic characterics of any version.
SWITCH NAME “ON” DESCRIPTION “OFF” DESCRIPTION
+GE MOSFET clipping only (all versions but v1.4). Default position
for v1.7 specs.
Adds D2 and/or D3 in series with Q1 and Q2.
With one OFF and one ON, it’s equivalent to v1.4.
With both OFF, it’s equivalent to the V2 Custom
Shop Germanium.
HI CUT Adds C11 (10n) in parallel with C4 (v1.5), which cuts more
highs before the clipping stage.
1n hi-cut capacitor only (all versions but v1.5).
Default position for v1.7 specs.
+BASS Adds C12 (33n) in parallel with C3 (v1.1 - 1.3) for ~100n total,
which increases bass before the clipping stage.
68n capacitor value (v1.4 and later). Default
position for v1.7 specs.
+MIDS (left sw.) Adds C10 (47n) in parallel with C8 for ~100n total (v1.1 and
1.2) if the other +MIDS switch is ON.
If the other +MIDS switch is OFF, the total is 68n, which does
not correspond to any version but is a useful in-between value.
47n tone cap (v1.3 and later). Default position for
v1.7 specs.
+MIDS (right sw.) Bypasses C9 (47n), which keeps the tone capacitor value at
47n (v1.3 - 1.7). Default position for v1.7 specs.
Adds C9 (47n) in series with C8, which halves the
tone cap value to ~22n (v2.0).
Note: On the PCB, the switch positions are labeled according to what they do if the lever is moved toward the label, which is sometimes ON and
sometimes OFF. In the table above, the “ON” description refers to the lever being moved up, regardless of the placement of the label on the PCB. Most
DIP switches will have text on the switch itself indicating which position is ON.
Other version changes
There are a few other changes that are impractical or obscure that we have not included as switchable
options, but if you’re curious about the other differences then here are the full details for each.
VERSION DESCRIPTION
1.1 Drive 500kA; Tone 25kA; Volume 100kB; op-amp capacitor 100n (+BASS set to “ON”); tone capacitor 100n (both +MIDS
set to “ON”); no GE clipping (both +GE set to “ON”)
1.2 Same as v1.1, but Volume 500kB
1.3 Drive 1MA; Tone 10kB; Volume 500kB; op-amp capacitor 100n (+BASS set to “ON”); tone capacitor 47n (left +MIDS set
to “OFF”, right +MIDS set to “ON”); no GE clipping (both +GE set to “ON”); C2 and C5 are 330pF (these are 220pf in all
other versions)
1.4 Drive 1MA; Tone 10kB; Volume 500kB; op-amp capacitor 68n (+BASS set to “OFF”); tone capacitor 47n (left +MIDS set to
“OFF”, right +MIDS set to “ON”); asymmetric GE clipping (one +GE set to “OFF” and one set to “ON”)
1.5 Drive 1MA; Tone 10kB; Volume 100kA; op-amp capacitor 68n (+BASS set to “OFF”); tone capacitor 47n (left +MIDS set to
“OFF”, right +MIDS set to “ON”); add hi-cut capacitor (HI CUT set to “ON”); no GE clipping (both +GE set to “ON”)
1.6 Drive 1MA; Tone 10kB; Volume 100kB; op-amp capacitor 68n (+BASS set to “OFF”); tone capacitor 47n (left +MIDS set to
“OFF”, right +MIDS set to “ON”); remove hi-cut capacitor (HI CUT set to “OFF”); no GE clipping (both +GE set to “ON”)
1.7 Same as v1.6 (the version increment was due to upgraded filter capacitors). This is the version that is specified in the parts
list, and the version that was in production the longest.

TITAN DYNAMIC DRIVE 6
BUILD NOTES (CONT.)
Clipping switch
The SPDT clipping switch allows for two positions: stock (2N7000, with optional germanium diodes) or
LED clipping. The original OCD never used LED clipping in any version, but it’s a very common DIY mod
and it sounds fantastic in this circuit.
Looking at the schematic, you may notice that the LEDs are always connected. The stock clipping mode
has a lower clipping threshold than the LED pair, so when stock mode is engaged, the LEDs have no
signal left to clip and are out of the circuit. They only clip the signal when the stock mode is disabled.
Make sure to use a SPDT on-on switch, not the on-off-on type that is more often used for clipping diodes.
It will still work, but the middle position will be the same as LED clipping.
Germanium diodes
The Titan uses two germanium diodes as part of the optional clipping combinations. These days, the
Russian D9 series are probably the most readily-available NOS germaniums, and will sound great in this
circuit. But be aware that these Russian diodes have the stripe on the anode rather than the cathode,
meaning they should be inserted backwards according to the PCB silkscreen.
This isn’t an issue for circuits like the Klon or Distortion+ that just use two germanium diodes, since
it’s electronically identical whether they’re both the right way or both backwards. However, since this
circuit puts them in series with the MOSFETs, then if the germaniums are reversed in relation to the
MOSFET polarity, the path to ground will be blocked and only half the waveform will be clipped.
If you’re not sure what type of diode you have, it’s always best to check the polarity using a multimeter
to avoid a time-consuming mistake.

SCHEMATIC
TITAN DYNAMIC DRIVE 7
GND
1M
N5817
100uF
1MA
10kB
GND
100kB
+9V
100n
VA
100R
10k
22n
470k
10k
10k
GND
VB
47uF
GND
VB
TL082P
TL082P
VA
GND
220pF
18k
2N7000
68n
GND
10k 10k
1n
VB
LED
VB
VB
150k
220pF
100n
39k
GND
1uF
33k
22k
47n
GND
GND
1k
33n
Ge
Ge
47n
GND
VB
10n
2k2
47n
IN
OUT
RPD
D1
C14
DRIVE
1
2
3
TONE
1
2
3
VOLUME
1
2
3
1
C15
R14
R1
C1
R2
R12
R13
C13
2
3
1
IC1A
84
6
5
7
IC1B
C2
R3
Q1 Q2
C3
R5 R6
C4
D4 D5
CLIP
2
3 1
R7
C5
C6
R8
C7
R9
R10
C8
HP/LP
2
3
1
R11
C12
D2 D3
C10
SW 2A
SW 2C
SW 1B
SW 1A SW 1C
SW 2B
C11
R4
C9
GND

TITAN DYNAMIC DRIVE 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.
x: -0.65, y: +1.71 x: 0.65, y: +1.71
ø9/32” ø9/32”
x: -0.85, y: +0.66
ø1/4”
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)
ø3/8” ø1/2”
0.385”
0.625” 0.625”
ø3/8”
OUT DC IN
125B
VOLUME
HP/LP CLIPPINGTONE
DRIVE
FOOTSWITCHLED
x: +0.85, y: +0.66
ø1/4”
0 1 2
CM
0 1
INCH

TITAN DYNAMIC DRIVE 9
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

TITAN DYNAMIC DRIVE 10
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.

TITAN DYNAMIC DRIVE 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 (2023-03-24)
Initial release.