An effects unit, effects processor, or effects pedal is an electronic device that alters the sound of a musical instrument or other audio source through audio signal processing.
A guitar pedalboard allows a performer to create a ready-to-use chain of multiple pedals to achieve certain types of sounds. Signal chain order: tuner, compressor, octave generator, wah-wah pedal, overdrive, distortion, fuzz, EQ and tremolo.
Various type of guitar and bass effect pedals
An example of an effects chain. From the input [right] to the output [left]: Tuner [upper right] (tc electronic Polytune) ⇒ Wah pedal [lower right] (Morley Bad Horsie Wah) ⇒ Overdrives/distortion [lower row] (Rocktron Short Timer Delay → Danelectro CTO-1 Transparent Overdrive → Boss HM-2 → Boss MT-2) ⇒ Modulations/delay [upper row] (Digitech Hyper Phase → Danelectro CV-1 Vibe → Danelectro CT Tremolo → Digitech Hyper Delay)
Rackmounted effects in road cases. These road cases have the front protective panels removed so the units can be operated. The protective panels are put back on and latched shut to protect the effects during transportation.
A bass amplifier is a musical instrument electronic device that uses electrical power to make lower-pitched instruments such as the bass guitar or double bass loud enough to be heard by the performers
An Ampeg SVT cabinet with eight 10" speakers, with a separate Ampeg SVT amplifier "head" on top.
A Yamaha B100-115 combo amp, which contains a 100 watt amplifier and one 15" speaker in a wooden cabinet.
A Hartke 500 watt amp "head" on top of an Ashdown 4x10" speaker cabinet.
A 1930s era combo amplifier and a Rickenbacker electric upright bass from 1935.