Aion Electronics Azimuth Overdrive User manual

1ZENDRIVE / AZIMUTH OVERDRIVE
Azimuth Overdrive
Hermida/Lovepedal Zendrive
1313
13 13
Controls & Usage
The Zendrive has the following controls:
• Drive controls the amount of gain in the op amp feedback diode clipping stage.
• Tone controls the treble response of the effect.
• Voice controls the amount of bass while also changing the gain structure. As you turn it up, the available
gain range also increases.
• Volume controls the overall output.
Modications&Experimentation
This one won’t be a whole lot of fun for a tweaker. The Zendrive is what it is, and with such a low parts count, if
you start changing values around then it quickly stops being a Zendrive.
The Azimuth Overdrive project is a clone of the Hermida
/ Lovepedal Zendrive. It was rst released ... and in 2013
production was taken over by Lovepedal. The circuit has
changed very little since its inception, with the only major
change being the op-amp once Lovepedal took over.
The circuit is very basic, with a standard TS-style clipping
section followed by a variable R-C treble cut and a buffer.
The bass is adjustable via the “Voice” control, which
varies the corner frequency of the lter coming off the op-
amp. This also has the side-effect that the available gain
increases as the Voice control is turned up.
Despite the legendary stature of the Zendrive, the circuit
has the lowest parts count of any of my PCB projects and
is a great project for beginners.
Azimuth Project LinkOverview

2ZENDRIVE / AZIMUTH OVERDRIVE
Parts
1Op-ampselection: In the original, the back of the op-amp was sanded down, so while it’s not known for
sure, some expert DIY detectives found that it was almost certainly an AD712. The Lovepedal version uses an
unsanded NE5532. Due to the high diode-clipping threshold, this circuit has a particularly strong dependence
on the type of op-amp used, so it’s worth experimenting with a few. Other DIY favorites include the OPA2134,
OPA2604, TC2272, MC1458 and LM833.
2Clippingdiode:Some versions of the Zendrive use another BAT41 here instead of a germanium. It can be
any type of germanium diode, not just 1N34A.
3Drivepotvalue:The original uses 500kB (linear taper) but I recommend using a 500kA (audio taper).
4Volumepotvalue:The original uses 100kB (linear taper) but I recommend using a 100kA (audio taper).
Additional Part Notes
• Capacitors are shown in nanofarads (n or nF) where appropriate. 1000n = 1uF. Many online suppliers do
not use nanofarads, so you’ll often have to look for 0.047uF instead of 47n, 0.0056uF instead of 5n6, etc.
• The PCB layout assumes the use of lm capacitors with 5mm lead spacing for all values 1nF through
470nF. I prefer EPCOS box lm or Panasonic ECQ-B/V-series.
• Potentiometers are Alpha 16mm right-angle PCB mount.
• I recommend using these dust covers / insulators from Small Bear to insulate the back of the pots from
the board and prevent shorts. If you don’t use these, use some electrical tape or cardboard to act as
insulation. The right-angle pots will make direct contact with the solder pads otherwise.
Resistors
R1 470k
R2 1k
R3 1k
R4 10k
R5 1k
R6 10k
R7 10k
RPD 1M to 2M2
LEDR 4k7
Semiconductors
IC1 AD712 1
D1 1N4002
D2, D4 BAT41
D3 1N34A Ge 2
Q1, Q2 2N7000
LED 5MM
Potentiometers
Drive 500kA 3
Tone 50kB
Voice 10kB
Volume 100kA 4
Capacitors
C1 470n lm
C2 100pF MLCC
C3 100n
C4 3n3
C5 470n lm
C6 100uF electro
C7 47uF electro

3ZENDRIVE / AZIMUTH OVERDRIVE
Schematic
GND +9V
7k42M2
5MM
1N4002
100uF
500kB
100kB
GND GND
10k
10k
47uF
VR
GND GND
AD712
AD712
GND
470n
470k
VR
2N7000
2N7000
BAT41 1N34a
BAT41
100pF
50kB
1k
1k
10kB
100n
VR
10k
3n3
470n
1k
GND
GND
+9V
SW
IN
OUT
RDELDPR
LED
D1
C6
DRIVE
1
2
3
VOLUME
1
2
3
R6
R7
C7
IC1A
2 3
1
6 5
7
IC1B
84
C1
R1
Q1
Q2
D2 D3
D4
C2
TONE
1
2
3
R2
R3
VOICE
1
2
3
C3
R4
C4
C5
R5

4ZENDRIVE / AZIMUTH OVERDRIVE
GeneralBuildInstructions
These are general guidelines and explanations for all Aion Electronics DIY projects, so be aware that not
everything described below may apply to this particular project.
BuildOrder
When putting together the PCB, it’s recommended that you do not yet solder any of the enclosure-mounted
control components (pots and switches) to the board. Instead, follow this build order:
1. Attach the audio jacks, DC jack and footswitch to the enclosure.
2. Firmly attach the pots and switches to the enclosure, taking care that they are aligned and straight.
3. Push the LED1 into the hole in the enclosure with the leads sticking straight up, ensuring that the at side
is oriented according to the silkscreen on the PCB.
4. Fit the PCB onto all the control components, including the leads of the LED. If it doesn’t t, or if you need
to bend things more than you think you should, double-check the alignment of the pots and switches.
5. Once you feel good about everything, solderthemfromthetop2as the last step before wiring. This way
there is no stress on the solder joints from slight misalignments that do not t the drilled holes. You can
still take it out easily if the build needs to be debugged, but now the PCB is “custom-t” to that particular
enclosure.
6. Wire everything according to the wiring diagram on the last page.
1FortheLED: You can use a bezel if you’d like, but generally it’s easier just to drill the proper size of hole
and push the LED through so it ts snugly. If you solder it directly to the PCB, it’ll stay put even if the hole is
slightly too big. Make absolutely sure the LED is oriented correctly (the at side matches the silk screen) before
soldering, as it’ll be a pain to x later! After it’s soldered, clip off the excess length of the leads.
2Noteonsolderingthetoggleswitch(es): It will require a good amount of solder to ll the pads. Try to be as
quick as possible to avoid melting the lugs, and be prepared to feed a lot of solder as soon as the solder starts
to melt. I recommend waiting 20-30 seconds between soldering each lug to give it time to cool down.
“RPD”and“LEDR”resistors
The resistors marked “RPD” and “LEDR” are generally not original to the circuit and can be adjusted to
preference. “RPD” is the pulldown resistor to help tame true-bypass popping, while “LEDR” controls the
brightness of the LED. I generally use 2.2M for the pulldown resistor and 4.7k for the LED resistor.
Sockets
Since double-sided boards can be very frustrating to desolder, especially components with more than 2 leads,
it is recommended to use sockets for all transistors and ICs. It may save you a lot of headaches later on.

5ZENDRIVE / AZIMUTH OVERDRIVE
Drilling & Placement
Print this page and cut out the drilling template below. Tape it to the enclosure to secure it while drilling. Note
that the holes are shown slightly smaller than they need to be, so drill out the holes as shown and then step up
until they are the correct size for the components.
Parts Used
• Switchcraft 111X enclosed jacks
• Kobiconn-style DC jack with internal nut
Hammond1590B
(bottom/inside view)

6ZENDRIVE / AZIMUTH OVERDRIVE
Standard Wiring Diagram
This diagram shows standard true-bypass wiring
with a 3PDT switch. When the switch is off, the
input of the circuit is grounded and the input jack
is connected directly to the output jack.
The SW pad is the cathode connection for the
LED. This will connect to ground to turn it on
when the switch is on. Usage of the on-board
LED connection is not required if you have
specic placement needs for your enclosure,
but’s incredibly convenient.
The wiring diagram also makes use of star
grounding principles where all of the grounds
connect to a single ground point (in this case the
sleeve of the input jack). This is best practice
to avoid added noise caused by improper
grounding. The sleeve of the output jack is
unconnected.
If using a painted or powdercoated enclosure,
make sure both jacks have solid contact with
bare aluminum for grounding purposes. You may
need to sand off some of the paint or powdercoat
on the inside in order to make this happen.
Make sure to double-check the markings of the
pads on the PCB for your particular project – they
are not always in the order shown here!
IN GND OUT SW
+9V
SLEEVE
TIP
TIP
License / Usage
NodirectsupportisofferedforthesePCBsbeyondtheprovideddocumentation.It is assumed that you
have at least some experience building pedals before starting one of these. Replacements and refunds will not
be offered unless it can be shown that the circuit or documentation are in error. I have in good faith tested all of
these circuits. However, I have not necessarily tested every listed modication or variation. 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specicallynoted. No bulk
pricing or discounting is offered. 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, 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 pedal industry needs more transparency, not less!)