Based on Jon Dattorro’s Effect Design Part 1: Reverberator and Other Filters, located here: https://ccrma.stanford.edu/~dattorro/EffectDesignPart1.pdf
Erica Synths – EDU DIY Hi-Hat – Notes
A collaboration between Moritz Klein and Erica Synths.
Features
- TR-808 inspired circuit
- Manual Tune, Decay and Tone controls
- CV controlled Tune and Decay
- Accent input
- £65.00

Device Specifications
Item | Eurorack Synthesizer Module |
Brand | Erica Synths and Moritz Klein |
Model | Erica Synths – EDU DIY Hi-Hat – Notes |
Module Function | Hi-Hat Module |
Type | Analoge |
Frequency Controls | Tune, Tune CV |
Controls | Tone, Decay |
I/O | 1 Trigger, 1 Accent CV, 1 Tune CV, 1 Decay CV, 1 Output |
CV Span (full range) | -5V – +5V |
Accent | >+2.5V |
Power Supply | Power Consumption: 7mA@+12V, 7mA@-12V |
Height | 3U |
Width HP | 8 HP |
Depth | 30mm |
Resources
- YouTube > Moritz Klein > Designing a TR-606 style hi-hat from scratch – https://www.youtube.com/watch?v=zbBY7JL9nnQ
- Erica Synths > EDU DIY Hi-Hat – https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-hi-hat/
- Erica Synths > EDU DIY Hi-Hat > Manual – https://www.ericasynths.lv/media/HIHAT_MANUAL_1.pdf
Erica Synths – EDU DIY Snare Drum – Notes
A collaboration between Moritz Klein and Erica Synths.
Features
- Manual and CV controlled Tune
- Tune CV depth attenuator
- Manual Attack and Decay control
- Manual and CV Snappy (noise and tone crossfade) control
- Accent input
- £65.00

Device Specifications
Item | Eurorack Synthesizer Module |
Brand | Erica Synths and Moritz Klein |
Model | Erica Synths – EDU DIY Snare Drum – Notes |
Module Function | Snare Drum Module |
Type | Analoge |
Frequency Controls | Tune, Tune CV |
Controls | Attach, Decay, Snappy |
I/O | 1 Trigger, 1 Accent CV, 1 Tune CV, 1 Snappy CV, 1 Output |
CV Span (full range) | -5V – +5V |
Accent | >+2.5V |
Power Supply | Power Consumption: 7mA@+12V, 7mA@-12V |
Height | 3U |
Width HP | 10HP |
Depth | 30mm |
Resources
- YouTube > Moritz Klein > Designing a TR-808 style snare drum from scratch – https://www.youtube.com/watch?v=hULEn2_4Unw&t=567s
- Erica Synths > EDU DIY Kick Drum – https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-snare-drum/
- Erica Synths > EDU DIY Kick Drum > Manual – https://www.ericasynths.lv/media/SNARE_MANUAL_Q9zNEN3.pdf
Erica Synths – EDU DIY Kick Drum – Notes
A collaboration between Moritz Klein and Erica Synths.
Features
- Manual and CV controlled Pitch
- Accent input
- Manual decay control
- Manual pitch envelope with adjustable depth and decay time
- Tone control
- Distortion control
- £65.00

Device Specifications
Item | Eurorack Synthesizer Module |
Brand | Erica Synths and Moritz Klein |
Model | Erica Synths – EDU DIY Kick Drum – Notes |
Module Function | Kick Drum Module |
Type | Analoge |
Frequency Controls | Tune, Tune CV |
Controls | Tone, Decay |
I/O | 1 Trigger, 1 Accent CV, 1 Pitch CV, 1 Output |
CV Span (full range) | -5V – +5V |
Accent | >+2.5V |
Power Supply | Power Consumption: 6mA@+12V, 7mA@-12V |
Height | 3U |
Width HP | 10HP |
Depth | 30mm |
Resources
- YouTube > Moritz Klein > Designing a simple analog kick drum from scratch – https://www.youtube.com/watch?v=yz37Yz315eU&t=482s
- Erica Synths > EDU DIY Kick Drum – https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-kick-drum/
- Erica Synths > EDU DIY Kick Drum > Manual – https://www.ericasynths.lv/media/KICKDRUM_MANUAL_5wVQsEK.pdf
Ornament and Crime (o_C) – Notes
Polymorphic CV Generator

The Ornament & Crime (O_C) Eurorack Module is a collaborative open-source project by Patrick Dowling, Max Stadler (mxmxmx), and Tim Churches, originally designed as a quantizing ASR but expanded into a multi-purpose platform.
Ornament & Crime is a versatile, polymorphic control voltage (CV) generator that offers a variety of “apps” as part of its firmware. These apps can be selected on-the-fly without rebooting the module, making it a powerful tool for modular synthesis. Below is a list of the apps currently available in the standard Ornament & Crime firmware, based on its official documentation as of the latest known version (v1.3.x).
Apps Available in Ornament & Crime Firmware
- CopierMaschine
- An enhanced quantizing digital emulation of a four-stage analog shift register (ASR). It takes an input CV, quantizes it, and shifts it across four outputs with each trigger, with options for buffer length, transposition, and scale changes.
- Harrington 1200
- Provides neo-Riemannian Tonnetz transformations of triadic chords. It uses gate/trigger inputs to transform chords (e.g., parallel, leading-tone, or relative transformations), useful for generative harmonic progressions.
- Automatonnetz
- Combines Tonnetz chord transformations with a “vector” sequencer. It can function as both a chord sequencer and a melody sequencer, offering unique sequencing capabilities beyond traditional linear patterns.
- Quantermain
- A quad pitch quantizer for external voltages, featuring editable scales. It supports clocked or continuous quantization (latency < 100 microseconds) and includes internal CV sources like Turing Machines, May-Verhulst logistic maps, or byte beats for semi-random generation.
- Meta-Q
- A dual-channel quantizer with additional CV-assignable parameters, offering flexibility over Quantermain by sacrificing two channels for more control options.
- Quadraturia
- A wavetable-based quadrature LFO, inspired by an Easter egg in the Mutable Instruments Frames module. It generates four phase-shifted LFO outputs with customizable waveforms.
- Low-rents
- A dual strange attractor modulation generator based on Lorenz and Rössler systems, partially inspired by an Easter egg in the Mutable Instruments Streams module. It produces chaotic, evolving CV signals.
- Piqued
- A quad voltage-controlled envelope generator, building on Mutable Instruments Peaks code. It offers various envelope types (including looping), adjustable trigger delays, and a Euclidean “trigger filter” for rhythmic envelope generation.
- Sequins
- A dual-channel step sequencer with four “tracks” of up to 16 steps each. Tracks can be sequenced themselves, allowing for complex pattern generation.
- Dialectic Ping Pong
- A quad bouncing ball envelope generator, based on a hidden mode in Mutable Instruments Peaks. It simulates gravitational ball-like envelopes with adjustable parameters.
- Viznutcracker, sweet!
- A quad “byte beat” equation generator for creating 8-bit audio noises/tunes or CV sequences when clocked externally. Based on concepts introduced by Ville-Matias Heikkilä (viznut) in 2011.
- Acid Curds
- A chord quantizer (“harmonic quantizer”) and chord progression sequencer, allowing quantization of external pitch voltages into chords and sequencing of chord progressions.
- References
- A utility app that outputs specific reference voltages for tuning/calibrating VCOs and other modules. It includes a frequency meter, note tuner, BPM tempo meter, and closed-loop calibration mode.
Additional Notes
- There’s also an alternative firmware called Hemisphere Suite, which splits the module into two “hemispheres,” each running a different app from a distinct set (e.g., Dual Quantizer, Turing Machine-like Enigma). However, the list above pertains to the standard O_C firmware.
- These apps leverage the module’s four CV inputs, four trigger inputs, and four CV outputs, with functionality re-mapped via its OLED display depending on the selected app.
Features
- Teensy 3.2 / DAC8565
- Quad 16-bit CV generator w/ OLED display
- 14HP, depth ~ 25mm
Device Specifications
Item | Eurorack Synthesizer Module |
Brand | Clone (they all are) |
Model | Ornament and Crime Polymorphic Generator |
Module Function | Multi-Function |
Type | Digital |
Controls | 2 Pots, 2 Buttons |
I/O | 4 Trigger, 4 CV, 4 outputs |
Software | Arduino, C++, |
OS Requirements – Mac | OS X 10.6.8 or later, Google Chrome |
OS Requirements – PC | Windows 7 SP1 or later, Google Chrome |
Power Supply | Eurorack Power, Power Consumption*: +12V=90mA, -12V=5mA, +5V=0mA |
Height | 3U |
Width HP | Original Ornament & Crime (o_C): 14 HP Micro Ornament & Crime (uO_C): 8 HP 1U Ornament & Crime: 1U format Plum Audio OCP: 14 HP Plum Audio OCP X: 10 HP |
Depth |
Resources
Bill of Materials for O+C (rev 2d, 2e)
- If your board is is labelled 2e (on top of the board, underneath the ‘ornament and crime’ label), that’s rev 2e. previous versions differ only slightly.
- the BOM for rev 2c. can be found here
- The footprint for passives is 0805 throughout. using 0603 everywhere will work just as fine, of course.
- Versions prior to 2e: there’s five 3-pin pads for trimpots (input/output calibration): simply omit the trimpots; the calibration can be done entirely in software. use five jumper wires instead and, ideally, 0.1% resistors for the output stage: it’s cheaper and makes calibration easier.
SMD resistors (0805)
value | # | part | note |
100R | 4x | e.g. mouser # 279-1623096-1 | 1% |
220R | 4x | e.g. mouser # 279-CPF0805B220RE1 | 1% |
510R | 2x | e.g. mouser # 603-RC0805JR-07510RL | 1-5% |
2k | 1x | e.g. mouser # 660-RK73H2ATTE2001F | 1% |
10k | 1x | e.g. mouser # 660-RK73H2ATTD1002F | 1-5% |
24k9 | 4x | e.g. mouser # 756-PCF0805R-24K9BT1 | 0.1% |
33k | 8x | e.g. mouser # 660-RK73H2ATTD3302F | 1% |
47k | 2x | e.g. mouser # 660-RK73H2ATTD4702F | 1% |
75k | 4x | e.g. mouser # 660-RK73H2ATTD7502F | 1% |
100k | 4x | e.g. mouser # 279-CPF0805B100KE | 0.1% |
100k | 8x | e.g. mouser # 660-RK73H2ATTD1003F | 1% (or simply get 12 x 0.1%) |
SMD caps (0805) (25V or better)
value | # | type | note |
18p-22p | 4x | C0G/NP0 (!) | e.g. mouser # 77-VJ0805A180GXACBC |
330p-560p | 4x | C0G/NP0 | e.g. mouser # 77-VJ0805A561JXAAC |
100n | 12x | ceramic | e.g. mouser # 80-C0805C104K5R |
470n | 3x | ceramic | e.g. mouser # 77-VJ0805Y474JXJTBC |
1u | 2x | ceramic | e.g. mouser # 581-08055C105K4Z2A |
10u | 4x | ceramic (or tantal) | e.g. mouser # 81-GRM21BR6YA106KE3L |
ICs/semis
what | # | package | part |
MCP6004 | 1x | (SOIC-14) | mouser # 579-MCP6004T-I/SL |
OPA2172 | 2x | (SOIC-8) | mouser # 595-OPA2172IDR, and see note (†) below |
DAC8565 | 1x | (TSSOP-16) | mouser # 595-DAC8565IAPW, 595-DAC8565ICPW, 595-DAC8565IBPW, 595-DAC8565IDPW (††) |
MMBT3904 (NPN) | 4x | (SOT-23) | mouser # 512-MMBT3904 |
1N5817 (diode) | 2x | (DO-41) | e.g. mouser # 621-1N5817 |
LM4040 5v0 | 1x | (SOT-23) | e.g. mouser # 926-LM4040DIM350NOPB |
ADP150-3v3 | 1x | (TSOT) | mouser # 584-ADP150AUJZ-3.3R7 |
LM1117-50 | 1x | (SOT-223) | mouser # 511-LD1117S50 |
- (†) something fancier (= more suitable, $$) than TL072 should be used for the DAC output stage; using TL072 will be ok, but ideally, you want something with (very) low offset/noise/drift. for example: OPA2172, OPA2277
- (††) they’ll all work. (grades C and D have slightly better specs (re temperature stability), but it won’t really matter here)
Misc Through-Hole
What | # | Note | Part |
22uF cap | 2x | RM2.5 (35V or better) | e.g. mouser # 647-UPM1V220MDD1TD |
inductor | 1x | 10uH | e.g. mouser # 542-78F100-RC |
jacks | 12x | ‘thonkiconn’ (or kobiconn) | PJ301M-12 |
encoders | 2x | 24 steps w/ switch | e.g. 652-PEC11R-4220F-S24 (†) |
2×5 pin header | 1x | 2.54mm (euro power connector) | e.g. mouser # 649-67996-410HLF |
1×7 OLED socket | 1x | 2.54mm, low profile but not “machined” sockets with round holes for the pins – the square header pins on most OLED carrier boards will not fit sockets with round holes. Use the low-profile sockets indicated here, or equivalent -> | e.g mouser # 517-929870-01-07-RA |
1×14 socket | 2x | 2.54mm, socket for teensy 3.x | see note (††) |
1×14 pin header (to match) | 2x | 2.54mm, header for teensy 3.x | – |
tact switches | 2x | multimecs 5E/5G | mouser #: 642-5GTH935 (†††) |
+ caps | 2x | multimecs 1SS09-15.0 or -16.0 | mouser #: 642-1SS09-15.0, or -16.0 |
3mm spacer | 1x | ∅ 3M, 10mm | mouser #: 855-R30-1611000 (††††) |
- (†) rotary encoder w/ switch: for instance: mouser # 652-PEC11R-4220F-S24 (20 mm, ‘D’), 652-PEC11R-4220K-S24 (20 mm, knurled)).
- (††) best to use “machined pin” ones (also called “round” or “precision”): the pcb holes are small. Or these sockets from RS-Online are a good alternative and will accept standard square-pin 0.1 inch pitch headers.
- (†††) much cheaper is sos.
- (††††) plus 2x 6mm 3M (hex) screws, or 1x ~ 16mm M3/hex screw + nut.
MCU/Display
What | # | Note | Source |
teensy 3.2 / 3.1 | 1x | cut the V_usb/power trace! | oshpark / mouser # 485-2756 |
OLED | 1x | SH1106 or SSD1306 / 1.3” / 128×64 | 7-pin, see note (†) |
- (†) you can find these 1.3” displays on ebay or aliexpress for < 10$. as long as the description claims that they are SH1106 or SSD1306 and the pinout is:
- GND – VCC – D0 – D1 – RST – DC – CS, or
- GND – VCC – CLK – MOSI – RES – DC – CS, or
- GND – VDD – SCK – SDA – RES – DC – CS
- … then they should work (it’ll be the same OLED, just using different labels).
- make sure you get the right size: 1.3” (not 0.96”)!
- alternatively, the hardware/gerbers folder has .brd/.sch files for a/the OLED carrier board. in that case, you’d need to get the bare OLED. for example here (though there’s cheaper options for getting bare OLEDs).
Behringer – 2600 Analog Semi-modular Synthesizer – Notes
Item | Semi-modular Desktop/Rackmount Synthesizer |
Type | Analog |
Polyphony | Monophonic/Duophonic Mode |
Oscillators | 3 Pulse width modulation (PWM) on OSC 2 and OSC 3 |
Waveforms | Sawtooth, Pulse, Triangle, Sine, Pulse Width Modulation, Frequency Modulation |
Noise Generator | White Noise, Pink Noise, Low Frequency Noise |
Filter | 2-mode 4-pole Resonant Filter: 4012 circuitry (16kHz cutoff), 4072 circuitry (11kHz cutoff) |
Envelopes | ADSR envelope generator and AR envelope generator, featuring time factor control |
LFO | Dedicated LFO with square and triangle waveshapes |
VCA | Yes |
Sample and Hold | Yes |
Effects Types | Digital Spring Reverb |
Analog Outputs | 2 x 1/4″ TS (L/R), 2 x 1/8″ TS (L/R) |
Headphones | 1 x 1/8″ TRS |
MIDI I/O | In/Thru/USB |
Other I/O | 93 x Patch Points |
Pedal Inputs | 2 x 1/4″ TRS (interval latch, portamento) |
USB | 1 x Type B |
Software | Synthtribe |
OS Requirements – Mac | OS X 10.6.8 or later |
OS Requirements – PC | Windows 7 SP1 or later |
Power Supply | 12V DC power supply (included) |
Height | 4.3″ |
Width | 19″ |
Depth | 14″ |
Weight | 11.22 lbs. |
Manufacturer Part Number | 000-DNJ02-00010 |
Resources
Behringer – Model D Analog Synthesizer – Notes
Item | Semi-modular Desktop/Rackmount Synthesizer |
Type | Analog |
Polyphony | Monophonic/Duophonic Mode |
Oscillators | 3 Pulse width modulation (PWM) on OSC 2 and OSC 3 |
Waveforms | Sawtooth, Pulse, Triangle, Sine, Pulse Width Modulation, Frequency Modulation |
Noise Generator | White Noise, Pink Noise, Low Frequency Noise |
Filter | 2-mode 4-pole Resonant Filter: 4012 circuitry (16kHz cutoff), 4072 circuitry (11kHz cutoff) |
Envelopes | ADSR envelope generator and AR envelope generator, featuring time factor control |
LFO | Dedicated LFO with square and triangle waveshapes |
VCA | Yes |
Sample and Hold | Yes |
Effects Types | Digital Spring Reverb |
Analog Outputs | 2 x 1/4″ TS (L/R), 2 x 1/8″ TS (L/R) |
Headphones | 1 x 1/8″ TRS |
MIDI I/O | In/Thru/USB |
Other I/O | 93 x Patch Points |
Pedal Inputs | 2 x 1/4″ TRS (interval latch, portamento) |
USB | 1 x Type B |
Software | Synthtribe |
OS Requirements – Mac | OS X 10.6.8 or later |
OS Requirements – PC | Windows 7 SP1 or later |
Power Supply | 12V DC power supply (included) |
HP Size | 70HP |
Height | 3.5″ |
Width | 14.7″ |
Depth | 5.4″ |
Weight | 5.4 lbs. |
Manufacturer Part Number | 000-CQJ02-00010 |