Through-hole Braids

Features

• Through hole version of Mutable Instruments Braids
• Braids is a voltage-controlled monophonic digital sound source

Credits / Resources

• Ordered card set from Sourcery Studios on Tindie
  • Sound-Force.nl
  • Front Panel
• Vagrant environment for Mutable Instruments modules hacking
• Schematic
• BOM

Original Braids

• Braids page
  • Braids Manual

• 16 HP
• 25mm deep
• +12V@100mA, -12V@15mA
• Braids Through Hole version has differences
  • Output is PWM
  • A/D is 10-bits

Original Braids Features

AN ATLAS OF WAVEFORM GENERATION TECHNIQUES

• Braids is a voltage-controlled monophonic digital sound source.
• Sound source… like an oscillator? Not really.
  • Most of the timbres it generates are so complex that approaching them with a classic analog modular setup would require a full case of oscillators, filters, VCAs, waveshapers and ring-modulators – that’s why we call it a macro-oscillator – intricate digital synthesis algorithms wrapped in oscillator’s clothes.
• 2 KNOBS TO RULE THEM ALL
  • Each algorithm is controlled by two continuously variable parameters, TIMBRE and COLOR, both of them voltage controllable.
  • Instead of being directly assigned to the intricate details of the synthesis algorithm, they work as meta-parameters going through all the sweet spots.
  • Very often, these parameters simultaneously affect several dimensions of timbre, creating very complex movements which would be hard to generate with a traditional setup.
• Synthesis models
• The classics
  • CS-80 style sawtooth with a notch.
  • Continuously variable morphing between triangle, sawtooth, square and pulse, with character control.
  • Square/sawtooth with pulse width control.
  • Triangle to sine morphing, with wavefolder.
• Direct digital synthesis
  • Band-limited dual pulse train, with detuning.
  • Dual square or sawtooth oscillator with hard sync.
  • Triple saw, square, triangle or sine.
  • Stack of three ring-modulated sine waves.
  • Swarm of seven sawtooth waves.
  • Comb-filtered sawtooth wave
  • Circuit-bent sawtooth generator with sample rate reduction and bit toggling.
  • Direct synthesis of filtered waveforms, casio CZ style.
  • Low-fi or hi-fi vowel/formant synthesis.
  • Harmonic oscillator.
  • FM with various feedback paths.
• Physical and percussive models
  • Plucked string (Karplus Strong).
  • Bowed string.
  • Reed and flute.
  • Bell and metallic drum.
  • 808 bass drum, cymbal noise and snare drum.
• Wavetables
  • 256 waveforms, organized as 21 wavetables or as a 16x16 XY map.
  • 4-note chord synthesis.
• Noise sources
  • Noise processed by a tuned multimode filter.
  • Noise processed by a dual BP filter.
  • Clocked digital noise.
  • Cloud of sinusoidal grains.
  • Particle synthesis.
• Additional settings
  • These settings are accessible through a menu, and are not CV controllable.
  • Bit-depth (from 4 to 16 bits) and sample rate (from 4kHz to 96kHz).
  • Quantizer on the CV-input with a large selection of scales.
  • Analog VCO-style linear detuning of higher frequencies.
  • Analog VCO-style pitch drifting.
  • Waveform quirks, unique to each module built.
  • Built-in AD envelope, assignable to the oscillator frequency, the COLOR and TIMBRE parameters, and to the amplitude.
  • META mode enabling CV-controlled model selection with the FM input.
• Specifications
  • All inputs: 100k impedance, DC to 4kHz.
  • 12-bit CV capture.
  • 96kHz, 16-bit audio processing (some algorithms are 2x or 4x oversampled).

STM32 "Blue Pill"

• "Blue Pill" Pins

• "Blue Pill" Schematic

Show Screen Caps

• From sound-force

Braids Show Notes

• Get the PCB set with panel and both PCBs for 9$ at Kristian's Tindie store
  • Tindie store
  • (Or) Download the Gerber files
• Get a STM32 Programmer here
• STM32F013CBT8 (128kb version) on ebay... not that many to choose from :/
  • The STM32F103C8T6 is the 64kb version and thus too small but SOMETIMES they are 128kb
• Front panel gerber by MyModularJourney
• Braids illustrated. all the waveforms explained
• Emilie Gilet / Mutable Instruments modules Github
  • Braids specific files
• Modular in a Week playlist
• Support Kristian's work on Patreon
• Kristian's Discord server - where you find the mi-th-braids channel and much more]
  • See mi-th-braids channel
  • See pinned messages
• Braids Manual

Build

• Assembly Notes

The PCBs were drawn with both parts numbers and part values on, so you can work faster without checking the BOM every 5 seconds. I also added PDFs of the PCB silkscreens on the project page, as the printed silkscreens can be sometimes low resolution and difficult to read.

Recommendations:

- Always start with the lowest profile part (resistors) and then move on to next “in height”
- Check twice, solder once!!
- It’s better to solder all the resistors located around the display at the BACK of the PCB, as they are quite close to the edge of the display.
- It’s better to solder the display when the front panel has been mounted so you can make it as flush as possible with the back of the from panel.
- The STM32F103/blue pill needs to be soldered at the back!!
- Use female headers for the STM32F103!
- You can use sockets for all the ICs, especially if you are starting with Synth DIY
- You can screw the voltage regulators to the PCB for better heat sinking using M3 screw and nut
- The voltage reference have different grades (A, B, C, D), A means the best. MI uses C grade for all CV inputs (VOCT as well). But you can use B or A, use D will probably not ruin your module.
- The voltage regulators could be either LM or LD1117
- If you got a V1.0 PCB, you won’t need R22 and Q7 around the analog 3.3V voltage regulator

Processing Card

Controls Card

Parts List

Controls Card Parts List

Qty	Index	Desc
14	R4-R10, R12-R18 (R4-R9 on rear)	100 Resistor, 1%
1	R51	330 Resistor, 1%
7	R1-R3, R11, R22, R23, R55 (R1-R3 on rear)	1k Resistor, 1%
1	R27	10k Resistor, 1%
1	R50	20k Resistor, 1%
10	R30, R31, R34, R35, R41-R44, R52, R53	24.9k Resistor, 1%
2	R45, R46	39k Resistor, 1%
2	R25, R26	49.9k Resistor, 1%
6	R24, R29, R47, R48, R54, R56	100k Resistor, 1%
1	R39	120k Resistor, 1%
3	R28, R32, R40	200k Resistor, 1%
3	R33, R49, R57 (Optional see note, only on Brain 1.2)	47 Resistor, 1%
1	C29	47p Capacitor, ceramic
2	C21, C22	100p Capacitor, ceramic
4	C13, C14, C16, C17	1n Capacitor, ceramic
13	C1-C6, C18, C20, C23, C26, C27, C28, C31	100n Capacitor, ceramic
1	C8	470n Capacitor, ceramic
1	C24	10u Capacitor, electrolytic NP
4	C7, C9, C15, C33	10u Capacitor, electrolytic
2	C25, C30	47u Capacitor, electrolytic
2	D1, D2	1N5817
2	IC1, IC2	SN74HC595
1	IC3	2.5V LM4040 Shunt Vref
1	IC4	MCP3204 quad 12-bit ADC
1	IC5	MCP4822 dual 12-bit DAC
2	IC6, IC11	3.3V LD1117V33
1	IC7	MCP6004 dual op-amp R2R IO
1	IC8	10V LM4040 Shunt Vref
1	IC9	TL074 quad op-amp
1	IC10	TL072 dual op-amp
6	Q1-Q4, Q6, Q7	NPN transistor 2N3904
1	UC1	STM32F103C8T6 NEEDS TO BE 124kb

Display Card Parts List

• 5pcs Red Common Cathode 14 segment display - MAKE SURE TO CHOOSE COMMON CATHODE

Qty	Index	Desc
2	DISP1, DISP2	Red Common Cathode 14 segment display
6	COLOR, FM, OUT, TIMBRE, TRIG, VOCT	Vertical jack connector
6	R19-R21, R36-R38	10k linear pot, 15mm shaft
1	SW1	Encoder, 24 steps w/ clicks, w/ switch
	Headers
	Single row male	1X06, 1X10, 1X8, 1X09
	Single row female	1X10, 1X8, 1X09,
2	Female header for the blue pill (optional)	1x20
	Euro power	2x05 (Preferably shrouded)
	Programmer
	Programmer to program the STM32 board
	Alternative Serial "programmer"	or FTDI's or CH430

Software

• ST-Link V2 pinout - corrections to pinout
• Software backup

Uploading Code to Blue Pill

• ST Link V2
• Before programming, set jumpers on Blue Pill module set towards center of card
• Use STMCubeProgrammer software to program card

• After programming, set jumpers on Blue Pill module set towards USB jack