mbhp_genesis
Differences
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mbhp_genesis [2017/08/13 14:51] sauraen [Component stuff chart] |
mbhp_genesis [2017/08/13 14:55] sauraen [Construction differences by sound chip type] |
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| For the OPN2 chips, the YM3438 is a complete reimplementation of the YM2612 in CMOS instead of NMOS. They also changed the output stage to get rid of some analog error in the YM2612's DAC, which produces a distinctive "ladder effect" sound in the audio output, as well as making the output about 10-20dB louder (which also produces excellent signal-to-noise performance). FM synthesis purists might be inclined to choose the YM3438; retro gaming fans will probably go with the YM2612, as this is the physical chip used in the Mega Drive / Genesis Model 1. | For the OPN2 chips, the YM3438 is a complete reimplementation of the YM2612 in CMOS instead of NMOS. They also changed the output stage to get rid of some analog error in the YM2612's DAC, which produces a distinctive "ladder effect" sound in the audio output, as well as making the output about 10-20dB louder (which also produces excellent signal-to-noise performance). FM synthesis purists might be inclined to choose the YM3438; retro gaming fans will probably go with the YM2612, as this is the physical chip used in the Mega Drive / Genesis Model 1. | ||
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| + | (Note about the next two paragraphs: the resistor values given in the parts list are the ones I used and tested for each of YM2612 and YM3438, there's no clipping or other issues. If you don't want to experiment, use those.) | ||
| The differences for this module are relatively simple. For a YM2612, the audio outputs require a known load to perform to spec--these are R8 and R9. The value of 2.2k was taken from the [[http://www.sega-16.com/forum/showthread.php?26568-Introducing-the-Mega-Amp-The-universal-Genesis-audio-circuit|Mega Amp design]], but some experimentation may be warranted. | The differences for this module are relatively simple. For a YM2612, the audio outputs require a known load to perform to spec--these are R8 and R9. The value of 2.2k was taken from the [[http://www.sega-16.com/forum/showthread.php?26568-Introducing-the-Mega-Amp-The-universal-Genesis-audio-circuit|Mega Amp design]], but some experimentation may be warranted. | ||
mbhp_genesis.txt ยท Last modified: 2023/09/05 04:19 by sauraen
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