Glossary

Technical terms used in blog posts. If you don’t know what something means, look it up here.

Guitar and Audio

Plexi

Nickname for the Marshall Super Lead, a ’60s tube amp that defined the British rock sound

JCM800

Marshall ’80s version, same topology as the Plexi with more gain

1960A

Marshall 4x12 cabinet (4 x 12-inch speakers), the rock standard

Greenback

Celestion G12M-25, a 25W speaker with warm, creamy midrange

Preamp

Preamplifier — the stage that adds gain and saturation to the guitar signal

Cab

Cabinet — the speaker enclosure the amp connects to

Cranked

Amp with volume maxed out, naturally saturating

Scooped mids

Midrange frequencies attenuated — a “hollow,” aggressive sound

Twang

Bright, dry sound with more treble and less bass

Tone stack

EQ (equalization) circuit of an amp or pedal

FMV

Passive 3-knob tone stack format (Bass/Mid/Treble), used by Fender, Marshall, and Vox

Presence

Treble control via negative feedback from the power amp

Boost

Gain increase — usually an extra saturation stage for solos

Channel switch

Switching between two amp channels (or pedals with 2 voicings)

Downstrokes

Picking technique using only downward strokes — Johnny Ramone’s signature

Mosrite

Japanese guitar brand used by Johnny Ramone (Mosrite Ventures II)

Bridge pickup

Pickup near the guitar’s bridge — brighter, more aggressive sound

Electronics

JFET

Junction Field-Effect Transistor — transistor with response similar to a vacuum tube

12AX7

Preamplifier tube used in the Plexi (3 gain stages)

EL34

Power tube used in the Marshall Plexi’s power amp

mu-amp

Configuration of 2 JFETs that emulates the push-pull of a tube power amp

Push-pull

Final amp stage where 2 tubes work in opposition to generate power

Op-amp

Operational amplifier — IC that amplifies a signal with controllable gain

TL072

General-purpose op-amp, low noise, FET input — standard in DIY pedals

Trimpot

Adjustable potentiometer turned with a screwdriver — used to bias JFETs

Bias

Adjusting the operating point of a transistor/tube — affects the sound

PCB

Printed Circuit Board

Perfboard

Perforated board for circuit assembly (no traces, uses wires)

Protoboard

Solderless breadboard — for testing circuits before soldering

Diodo Zenner

Zener diode — a diode that regulates voltage, conducting in reverse at a fixed voltage

PTH

Plated Through-Hole — components with leads that pass through the PCB

Tântalo

Tantalum — a type of electrolytic capacitor, smaller and more stable than aluminum

Pedals and Effects

True Bypass

Signal passes straight from input to output without going through the circuit when the pedal is off

3PDT

Triple Pole Double Throw — footswitch that switches 3 circuits simultaneously

Footswitch

Pedal button pressed with the foot to turn effects on/off

TS 1/4”

1/4” (6.35mm) Tip-Sleeve jack — standard guitar connector

TRS 1/4”

1/4” (6.35mm) Tip-Ring-Sleeve stereo jack — used for balanced or stereo signals

DC 9V

9-volt power supply — standard for guitar pedals

LED

Light Emitting Diode — visual status indicator on a pedal

Stompbox

Another name for a guitar effects pedal

Digital Audio

IR (Impulse Response)

Digital “impression” of a cabinet + speaker + microphone response (a .wav file)

Convolução

Convolution — mathematical operation that applies the IR response to the audio signal

IR Loader

Device or software that loads and applies IRs in real time

USB Audio Interface

Device that converts analog audio to digital via USB (and vice versa)

ADC

Analog-to-Digital Converter — converts an analog signal to digital

DAC

Digital-to-Analog Converter — converts a digital signal to analog

Balanced (XLR)

Balanced signal — 2 signals (hot+cold) + ground, rejects noise in long cables

Unbalanced (RCA/TS)

Unbalanced signal — 1 signal + ground, susceptible to noise in long cables

Open Source and DIY

Open hardware

Hardware with public schematics, PCB, and BOM — anyone can build it

CC BY-NC-SA 3.0

Creative Commons Attribution-NonCommercial-ShareAlike — use/modify/share allowed, selling is not

AIAB

Amp In A Box — pedal that emulates a complete tube amp

DIY

Do It Yourself

BOM

Bill of Materials — component list with prices

Runoffgroove

Site with open hardware pedal circuits (tubes-to-FETs)

Zuko

Pedal name — the fire prince from Avatar: The Last Airbender. Fire = saturation, duality = 2 channels

Stem Separation (Phase 3+)

Stem separation

Separating an audio mix into individual tracks (vocals, drums, bass, guitar)

Demucs

AI model from Meta/Facebook for stem separation

RTF

Real-Time Factor — how long the processor takes to process 1s of audio

Backing track

Accompaniment track (music without one instrument, e.g., without guitar)

Mechanical Keyboards

Switch

Individual mechanism under each key — defines typing feel and sound

Cherry MX

Most common mechanical switch standard — varieties Red, Brown, Blue, etc

ALPS

Older type of mechanical switch — tactile and hard to find today

Keycap

Plastic cap that sits on the switch — the part you touch

Keycap profile

Keycap shape/height (SA, DSA, XDA, Cherry) — affects ergonomics and appearance

Plate

Metal plate where switches mount — the keyboard’s structure

Case

Keyboard housing — contains PCB, plate, and switches

Sandwich case

Case made of layered (acrylic/MDF) sheets bolted together

Handwired

Keyboard built by soldering switches with wires directly to the microcontroller (no PCB)

Hotswap

Sockets that allow swapping switches without soldering

Stabilizer

Mechanism that stabilizes large keys (Space, Enter, Shift)

Costar

Type of stabilizer with a metal bar and hooks

Underglow

LEDs on the underside of the keyboard — lighting visible through a translucent case

Backlight

LEDs under each key — illuminate keycaps from below

QMK

Quantum Mechanical Keyboard — open source firmware for custom keyboards

Bootloader

Program that allows flashing firmware to the microcontroller via USB

HID

Human Interface Device — USB class that makes a PC recognize a keyboard/mouse

ATMEGA328

8-bit AVR microcontroller from Atmel — the brain of the Arduino Pro Mini

RP2040

ARM Cortex M0+ microcontroller from Raspberry Pi — 133MHz, 264kB RAM

AVR

Family of 8-bit microcontrollers from Atmel/Microchip

USBaspLoader

V-USB bootloader that emulates USB on AVR without native USB hardware

USBAsp

External programmer for flashing AVR microcontrollers

Standalone

ATMEGA328 circuit built without the Arduino board (just the chip + crystal)

I2C

2-wire communication bus (SDA/SCL) between chips

WS2812B

Addressable RGB LED — each LED has its own address on the strip

SK6812

Addressable RGB LED, smaller than WS2812B — fits under keys

6028R

RGB LED with 3 separate channels (R/G/B) in one package

swillkb

Web tool that generates keyboard case files from a layout

keyboard-layout-editor

Web tool for designing keyboard layouts

40percent.club

Site with compact keyboard projects (40% of keys)

Gherkin

40% (3x10) open source keyboard from 40percent.club

Plaid

48-key open source keyboard with ATMEGA328 and USBaspLoader

Git and Servers

Self-hosted

Software hosted on your own server instead of a third-party service

VPS

Virtual Private Server — a virtual server you rent

CGI

Common Gateway Interface — runs programs on the web server to generate pages

cgit

Web interface for git repositories, in C, runs via CGI

stagit

Static page generator for git repositories

Merge Request

In GitLab, the equivalent of a GitHub Pull Request

Pull Request

Proposal to merge one branch into another on GitHub

Mirror

Automatic copy of a repository between servers

systemd

Service manager (init) standard on Linux

journalctl

Command to query systemd logs

Suckless

Minimalist software philosophy — small programs that do one thing well

Game Development

SDL2

Simple DirectMedia Layer 2 — C library for 2D graphics, audio, and input

Engine

Framework that abstracts the game loop, rendering, physics, etc

Game loop

Main cycle: input → update → render, repeated every frame

Godot

Open source game engine, in C++, with GDScript/GDNative

GDNative

Godot’s interface for C/C++ extensions (and other languages)

Tetrominó

Tetris piece — 4 blocks in an arrangement (I, O, T, S, Z, L, J)

Dear ImGui

C++ immediate-mode UI library — menus and debug overlays

WebAssembly

Binary format that runs C/C++ in the browser at near-native speed

Emscripten

LLVM → WebAssembly compiler — brings C/C++ code to the web

FOSS

Free and Open Source Software

Análise estática

Static analysis — analyzes code without running it, finding bugs via patterns (e.g., gcc -fanalyzer)

Makefile

make script that automates project compilation

Nuklear

C immediate-mode UI library — lightweight, no dependencies

LVGL

Light and Versatile Graphics Library — graphics for embedded systems

Embedded Electronics and DIY Audio

ESP32

Microcontroller with WiFi+Bluetooth, dual-core — the ESPBoy base

DevKit

Development board with the microcontroller exposed

GPIO

General Purpose Input/Output — digital pin on a microcontroller

Menuconfig

ESP-IDF configuration system (ESP32 SDK)

ROM

Game file (Read-Only Memory) — the emulated cartridge image

Emulação

Emulation — reproducing a console’s hardware in software on another device

TFT

Thin-Film Transistor — a type of color LCD display

Backlight

Lighting behind the LCD display — controls brightness

PAM8403

Class D audio amplifier IC, 3W×2 — used in DIY projects

TP4056

Lithium battery charger IC — standard in battery-powered projects

Divisor de tensão

Voltage divider — resistor circuit that divides voltage to read multiple buttons on one pin

Buzzer

Small piezo speaker — generates tones (not polyphonic)

SD Card

Memory card for storing ROMs and data

MOSI/MISO/SCLK/CS

SPI bus pins for displays and SD cards

Email and Infrastructure

Yunohost

Self-hosted system for managing web apps, email, and DNS on a VPS

Postfix

Email server (MTA) for sending and receiving SMTP messages

Porta 25

Port 25 — standard SMTP port for email sending, frequently blocked by ISPs

SMTP Relay

Third-party service (SendGrid, etc) that sends email on your behalf when port 25 is blocked

SendGrid

Twilio’s SMTP relay service — enables transactional email sending

iptables

Linux firewall — controls ports and network traffic

Firewall

Layer that filters network traffic by port/IP — can block email

Web and Design

Keyframe

Point in a CSS animation that defines element state at a specific moment

@keyframes

CSS rule that describes the keyframe sequence of an animation

Prompt

Terminal indicator (e.g., $) — where you type commands

Typewriter effect

Animation that simulates typing character by character

dmenu

Dynamic menu from the suckless project for X11 — basis for many tools

This glossary is updated as new posts are published. If you think a term is missing, let me know.