The
YM-2413, also called
OPLL, is a very low budget sound chip manufactured by
Yamaha and based on their YM-3812 (OPL2). To reduce manufacturing costs of the chip, many of the internal registers were removed. The result of this is that the YM-2413 can only play one user defined instrument at same the time. The other channels have to play one of the 15 built-in instruments. There were other cost cutting modifications such as having only 2 waveforms, and not having the channels added together - instead, the chip's DAC plays each channel one after the other, and the output of this is usually passed through an (analog) filter.
Notable uses of the YM-2413
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The YM-2413 was not included in the Sega Master System (European/American version of the Mark III).
