rabid.audio

Documenting my work at the intersection of technology and music.

Resources

Reference

Schematics

Datasheets

ADC

ADS1110

16-bit ADC

Datasheet

ANALOG

LM13700

Dual Operational Transconductance Amplifier (OTA)

This is the heart of most of my voltage-controlled designs.

Datasheet

TL07x

General purpose JFET Operational Amplifier (Op-amp)

This is my go-to op-amp. Solid, easy to use, audio quality. Comes in single, dual, and quad packages. Note that the power supply pins on the TL074 are opposite what you’d expect! They don’t make good comparators because they aren’t rail-to-rail, and they have pretty high power supply requirements so they may not be usable in all situations.

Datasheet

MN3102

Clock driver for BDD

Paired with an MN3207. Technically you can generate the clocks yourself, but you also need a 14/15*Vdd power input so you might as well use it.

Datasheet

MN3207

1024-stage BBD

Supports delays from 2.56ms to 51.2ms

Datasheet

VTL5C

Vactrol

A vactrol is an LED coupled to a light-dependent resistor.

Datasheet

Xvive5C3

Vactrol

A vactrol is an LED coupled to a light-dependent resistor.

Datasheet

LM386

Stereo amplifier

Classic chip for making headphone amplifiers and such. Though it’s supposed to be low noise, I’ve had a lot of noise problems with these. But it’s got relatively accessible power supply requirements and a minimum of parts.

Datasheet

DAC

DAC8571

16-bit DAC

Datasheet

TLV5620

Quad 8-bit DAC

Datasheet

MAX5134

16-bit SPI DAC

Datasheet

MAX5215

16-bit I2C DAC

Datasheet

DIGITAL

PC817X

Photocoupler

Useful for MIDI

Datasheet

DM74LS74

Dual Flip-Flop

Datasheet

Quad Bilateral Switch

I don’t like using these. They have weird voltage requirements, and when the switch is off they connect the output to VSS (which is the negative rail in most dual-ended power supply circuits). I prefer the DG403.

Datasheet

DG403

Dual SPDT Bilateral Switch

These only come in SMD packages but they are better than the CD4066.

Datasheet

555

Multi-purpose timer

Ubiquitous timer. Can be used as a delay, square wave oscillator, etc. Calculator

Datasheet

SN74LS155

Dual 1-4 demultiplexer

Datasheet

JACK

35RAPC4BHN3

Stereo 3.5mm jack

These are very easy to find. They are stereo with plug switches for both tip and sleeve. I’ve designed a breakout board for these. However I’ve started to prefer the Thonkiconn jacks instead as they are vertical and match the Alpha 9mm pot height.

Datasheet

Thonkiconn

Thonkiconn 3.5mm jack

Very popular in Eurorack

Datasheet

Purchase

LED

HT16K33

16*8 LED Controller Driver

Used by many 7- and 14-segment display modules, for example Sparkfun and Adafruit. Adafruit Arduino Library

Datasheet

SM460281N

10mm 7-segment display

Doesn’t have a pin for the decimal place

Datasheet

RGB LED

5mm, Common anode

Datasheet

MICROPROCESSOR

ATTiny85

A full 8-bit AVR microprocessor in a tiny 8-pin package

Can be programmed via Arduino as long as you have a programmer (I use a USBasp) and the attiny library installed. It’s got an internal oscillator which is good enough for situations which aren’t time-critical, meaning it works with zero external parts required.

pinout

Datasheet

Docs

ATMega328P

8-bit AVR microprocessor that powers Arduino

The benefit of building around this chip is you can prototype with an Arduino, and then once you’re happy with the design, switch to operating the chip directly with a minimum of parts.

pinout

Datasheet

POT

Alpha 9mm pot

9mm pot

Popular in Eurorack. Come in Single/Dual and Linear/Audio taper.

Datasheet

Purchase

Alpha 9mm pot (dual gang)

Datasheet

EG2301

DPDT slide switch

Just a little shorter than Alpha 9mm pots but if you seat them a little high they’ll do fine.

Datasheet

Purchase

MD100AM2B

Motorized slide potentiometer

These are used in DAW controllers where the sliders can sync with the software. Haven’t found a use for them (yet).

Datasheet

PDB18

Bourns mini instrument potentiometers

Used in guitars. Available in linear and audio taper in several configurations.

Datasheet

PTV09

Bourns 9mm potentiometer

Competitor to the Alpha ones

Datasheet

REGULATOR

LM317

1.5A adjustable voltage regulator

Output voltage is set with a pair of external resistors. For a hard-coded 5V output with no extra parts, use the LM7805.

Datasheet

LM337

Negative adjustable voltage regulator

Same as LM317 but for negative voltages

Datasheet

LM7805

1.5A 5V voltage regulator

Output fixed to 5V

Datasheet

TLE2426

"Rail Splitter" virtual ground

Given a power input, these will output a stable voltage half-way between them. This is very useful for creating dual-ended power supplies needed for most op-amp circuits in situations where your power supply is limited (e.g. a 9V stompbox).

Datasheet

Purchase

SWITCH

MTS mini toggle switch

13mm toggle switches with comparable hight to Alpha 9mm pots

Datasheet

RM subminiature rotary switch

Datasheet

PEC11R

Bourns 12mm incremental rotary encoder

Datasheet

PEC11H

Bourns 11mm incremental rotary encoder

Datasheet

TL1105

E-Switch momentary push button switches

Datasheet

Purchase

Purchase caps

TRANSISTOR

2N5457

N-Channel JFET

Datasheet

2N7000

N-Channel MOSTFET

Datasheet

AOD4286/AOI4286

100V N-Channel MOSFET

Datasheet

BS250

60V P-Channel MOSFET

Datasheet

DMMT5401

PNP matched-pair BJT

These can be a lot more useful than hand-matching transistors, but they are SMD.

Datasheet

DMMT5551

NPN matched-pair BJT

These can be a lot more useful than hand-matching transistors, but they are SMD.

Datasheet

FQP13N

60 V N-Channel MOSTFET

Datasheet

J175

25V N-Channel JFET

Datasheet

J175

30V P-Channel JFET

Datasheet