Aion Electronics Nebula DS-830 Distortion Master User manual

1MAXON DS-830 DISTORTION MASTER / NEBULA DISTORTION
Nebula
Maxon DS-830 Distortion Master
Nebula Project LinkOverview
31
The Nebula Distortion is a clone of the Maxon DS-380, a
relatively new addition to Maxon’s line of pedals but one that
maintains the spirit of their innovations in the 1980s.
Despite being a relative late-comer, the circuit is a very worthy
addition to Maxon’s product line and retains the spirit and
character of their classic designs: a JRC4558D op-amp with
feedback-diode clipping like the Tube Screamer, plus some
interesting twist that makes it unique. In this case, it’s a two-band
gyrator tonestack (not dissimilar from a Boss HM-2 Heavy Metal)
that offers a great deal more exibility and imparts a very different
tonal character than the typical amp-like passive tonestack.
Controls & Usage
• Gain controls the amount of gain from the op amp that is fed through the feedback clipping diodes.
• Level is the output level of the effect.
• Bass allows you to adjust the low-end response of the circuit via a gyrator-based tone control.
• Treble allows you to adjust the high-end response of the circuit, also via a gyrator tone control.
Modications
This is a tight layout, so you won’t nd any of the “standard” Aion modications such as a clipping diode switch.
However, there are extra pads for the soft clipping diodes clipping diodes (D2 through D5) in case you want to
stack two diodes in series—for instance, two 1N914s or one 1N914 and one BAT41 on each side. The stock
unit only uses one in each direction.
For the hard-clipping diodes, I’ve included the “Soft” trimmer which is on most of my other hard-clipping
circuits. This allows you to put some resistance in series with the hard-clipping diodes which reduces their
effect and softens the hard-clipping somewhat. When turned all the way down, it’s fully removed from the
circuit, so I recommend including it.
Any other standard-pinout dual op-amps will work in this circuit as well. Try a TL072 or OPA2104.
Like a Tube Screamer, you can adjust R7 + C5 to change the gain structure and the low-end rolloff frequency.
The stock corner frequency is 408 Hz. Just keep in mind you’ve got a bass control further along in the circuit so
you can dial out whatever you don’t like.

2MAXON DS-830 DISTORTION MASTER / NEBULA DISTORTION
Parts
Resistors, cont.
R4 10k
R5 100k
R6 2k
R7 390R
R8 1k
R9 10k
R10 100k
R11 3k9
R12 220R
R13 10k
R14 10k
R15 560R
R16 10k
R17 22k
R18 3k
R19 510k
R20 10k
R21 100k
R22 470R
R23 10k
R24 10k
RPD 2M2
LEDR 4k7
Semiconductors
Q1 2N5457
Q2–Q4 2N5088
IC1 JRC4558D
D1 1N4002
D2, D5 1N914
D3–D4 jumper 1
D6–D7 1N914
LED 5mm LED
Potentiometers
Gain 250kA 2
Level 100kA
Bass 25kB 4
Treble 10kB
Soft 10k trim (3362P) 3
Capacitors
C1 100n
C2 3n9 4
C3 1uF lm
C4 10pF
C5 1uF lm
C6 10uF electro
C7 470n
C8 220n
C9 3.3uF electro
C10 47n
C11 100n
C12 3n3
C13 10uF electro
C14 100n
C15 10uF electro
C16 100uF electro
C17 47uF electro
Resistors
R1 10k
R2 1M
R3 10k
Build Notes
1Extra pads have been provided in case you want to double up on diodes in the feedback clipping section. For
a fully stock unit, jumper D3 and D4.
2The original uses a linear (B) taper for the Gain control, but I prefer an audio (logarithmic) taper here.
3If you want to exclude this control, jumper pads 1 & 2. I recommend including it because it’s out of the circuit if
turned all the way down. Extra space has been provided in case you want to use the larger 3386 trimmer.
2Prior to February 2017, all versions of the DS-830 schematic had C2 at 39n and the Bass pot at 5kB. C2
should instead be 3n9 and the Bass pot should be 25kB.
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.
• 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.

3MAXON DS-830 DISTORTION MASTER / NEBULA DISTORTION
Schematic
GND
+9V
7k42M2
5MM
1N4002
100uF
250kA
100kA
GND GND
25kB
100n
10k
1M
10k
10k
GND
47uF
GND
VA
2N5457
+9V
VA
10k
10k
GND
3n9
VA
1uF
100k
VA
JRC4558DJRC4558D
10pF
2k390R
1uF
VA
1k
GND
470n
10k
100k
VA
3k9
220n
3.3uF
2N5088
GND
220R
+9V
10k
10k
GNDVA
10kB
2N5088
560R
+9V
10k
22k
GNDVA
100n 3n3
3k
47n
GND
100n
510k
2N5088
VA
+9V
10k
GND
100k
GND
470R
10uF
10uF
10kB
10uF
+9V
SW
IN
OUT
RDELDPR
LED
D1
C16
GAIN
1
2
3
LEVEL
1
2
3
BASS
1
2
3
C1
R1
R2
R23
R24
C17
Q1
R3
R4
C2
C3
R5
2 3
1
IC1A
6 5
7
IC1B
C4
D3 D4
R6R7
C5
R8
D7
D6
C7
R9
R10
R11
C8
C9
Q2
84
R12
R13
R14
TREBLE
1
2
3
Q3
R15
R16
R17
C11 C12
R18
C10
C14
R19
Q4
R20
R21
R22
C15
C13
D5 D2
1
2
3
SOFT
C6

4MAXON DS-830 DISTORTION MASTER / NEBULA DISTORTION
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.
1For 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.
2Note 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.

5MAXON DS-830 DISTORTION MASTER / NEBULA DISTORTION
Drilling & Placement
Print this page and have an adult cut out the drilling template below for you. 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)
BASS TREBLE

6MAXON DS-830 DISTORTION MASTER / NEBULA DISTORTION
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!)