Yamaha is a Japanese company that manufactures audio equipment, among many other products. Their audio chips are often used on third-party sound cards.
The Yamaha OPL2 (YM3812) is the chip used on the original AdLib card and clones. This is an FM-synthesizer chip, featuring 9 two-operator channels. OPL2 is an abbrevation of 'FM Operator type L2'.
The Yamaha OPL3 (YMF262) is an extended version of the original OPL2 chip, adding an extra register base for a total of 18 two-operator channels. Twelve of these channels may be combined to form six four-operator channels. Each channel can be routed to a maximum of 4 output channels, though there are no sound cards that actually use all four. Normally only the first two channels are connected to a DAC (YAC512), providing crude stereo support. The first soundcards equipped with an OPL3 chip include the Creative Sound Blaster Pro 2 and the AdLib Gold. OPL3 is an abbrevation of 'FM Operator type L3'.
The Yamaha OPL3-SAx is an all-in-one sound chip, featuring SBPro2, WSS, MPU-401 and OPL3 compatibility. Chipsets featuring it include YMF-701, YMF-711, YMF-715, YMF-718 and YMF-719. The last two are probably rebranded YMF-715s.
Drivers include a XG-compatible softsynth which although having some tuneable options is largely inferior to other such solutions from Yamaha. Windows 2000 and XP support these chipsets out of the box, requiring no external drivers. Sound cards using these chips were manufactured by Aopen, Labway, Genius and Addonics, possibly others.
The OPL3-SAx is a popular choice with retro gamers, and is often praised for its excellent compatibility and low noise level. Its MPU-401 interface does not suffer from the hanging note bug present in certain Creative sound cards. For best sound quality, the internal amp should be disabled by jumper and all settings in the driver set to zero and setting the output type to hi-fi. The main drawback of most cards with these chipsets is that they cannot house regular-sized daughterboards due to being too small. A possible workaround is creating an own cable.
Wave Blaster modules
Released in 1995, the Yamaha DB50XG is a wavetable synthesizer daughter card for the Wave Blaster connector. It is compatible with General MIDI and the Yamaha XG standards. The unit features 676 instruments, 16 Parts and maximum 32-note polyphony. It features 2 operation modes: XG and TG300B. The software synthesizer S-YXG50 is 100% identical to this particular series of hardware, with the 4 MB soundfont possibly being a dump of this card's ROM.
The Yamaha DB60XG is an extended version of the DB50XG, sold only in Japan. In the rest of the world this card is known as the NEC XR385. It is exactly identical to the DB50XG, with two extra analog sound inputs that can be routed through the effects processor. It is rumored that the analog inputs were meant for karaoke or related applications.
16-bit ISA expansion card, standalone version of the DB50XG/DB60XG. Features no codec and is only a pure XG synth.
The first XG compatible device, released in 1994. 729 instruments, 32 parts, 64-note polyphony.
Sound module version of DB50XG released in 1996, no LCD screen.