A sound chip is an integrated circuit (i.e. "chip") designed to produce sound (see chiptune). It might be doing this through digital, analog or mixed-mode electronics. Sound chips normally contain things like oscillators, envelope controllers, samplers, filters and amplifiers.
Programmable Sound Generators (PSG) 
- General Instrument
- Hudson Soft
- MOS Technology
- Texas Instruments
- Texas Instruments SN76477
- Texas Instruments SN76489 "DCSG", used in Sega SG-1000, BBC Micro, and Texas Instruments TI-99/4a.
- Texas Instruments SN76489A "DCSG", used in ColecoVision, Sega Master System, Sega Pico, Sega Game Gear, and Sega Mega Drive/Genesis.
- Texas Instruments SN76496, used in Tandy 1000.
Frequency modulation synthesis (FM synth) 
- Yamaha YM2413 (a.k.a. OPLL), used in MSX in MSX Music cartridges like the FM-PAC and internally in several Japanese models by Panasonic, Sony and Sanyo; also used in Sega Mark III (Japanese version of Master System)
- Yamaha YM2151 (a.k.a. OPM), used in Sharp X68000 and the Yamaha SFG-01 and SFG-05 FM Sound Synthesizer Unit cartridges for MSX
- Yamaha YM2203 (a.k.a. OPN), used in PC-88 and PC-98
- Yamaha YM2608 (a.k.a. OPNA), used in PC-88 and PC-98
- Yamaha YM2610 (a.k.a. OPNB), used in SNK Neo Geo
- Yamaha YM2612 (a.k.a. OPN2), used in Sega Mega Drive / Genesis
- Yamaha YM3526 (a.k.a. OPL)
- Yamaha YM3812 (a.k.a. OPL2), used in AdLib and early Sound Blaster sound cards
- Yamaha YMF262 (a.k.a. OPL3), used in Sound Blaster Pro 2.0 and later cards
- Yamaha YMF278 (a.k.a. OPL4), used in Moonsound cartridge for MSX
- Yamaha YMF288 (a.k.a. OPN3), used in PC-98
- Yamaha YMF7xx (Embedded audio chipset in some laptops and soundcards)
Pulse-code modulation (PCM, sample-based) 
See also 
- Sound generators of the 1980s home computers - Has a list of chips, pictures, datasheets, etc.