mbhp_genesis
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
|
mbhp_genesis [2017/08/13 14:51] sauraen [Component stuff chart] |
mbhp_genesis [2017/08/18 21:11] sauraen [Parts list] |
||
|---|---|---|---|
| Line 141: | Line 141: | ||
| | 1 | Y2 or Y4 | 3.58 MHz (or 4 MHz) oscillator | 520-TCH357-X | Oscillator (either half-size/8-DIP or 5x7mm SMD) at desired PSG frequency. MIDIbox Genesis firmware will correct frequencies to match original VGM pitch. | | | 1 | Y2 or Y4 | 3.58 MHz (or 4 MHz) oscillator | 520-TCH357-X | Oscillator (either half-size/8-DIP or 5x7mm SMD) at desired PSG frequency. MIDIbox Genesis firmware will correct frequencies to match original VGM pitch. | | ||
| | 3 | Q1, Q2, Q3 | 2N7000 or BS170 | 821-TSM2N7000KC821-T or 512-BS170 | Any small-signal N-channel MOSFET with the gate as the center pin; the board silkscreen is for 2N7000, if you use BS170 (as I did) mount them backwards to match the source and drain pins. | | | 3 | Q1, Q2, Q3 | 2N7000 or BS170 | 821-TSM2N7000KC821-T or 512-BS170 | Any small-signal N-channel MOSFET with the gate as the center pin; the board silkscreen is for 2N7000, if you use BS170 (as I did) mount them backwards to match the source and drain pins. | | ||
| - | | - | J1, J2, J5, J6, J7, J8 | 0.1" pin headers | Buy in bulk | Headers; J1, J2, and J7 connect all boards together, so put sockets on one side of the boards and have the pins sticking through on the other sides. J5 and J6 are individual on each board if used, and J8 is only on the final board. | | + | | - | J1, J2, J7, J10 | 0.1" stackable pin socket/headers | 782-A000086 | Pin sockets with long pins (from Arduino shields), for stacking the boards together. Buy in bulk and combine them for the appropriate sizes. Use a regular pin header for the lowest board in the stack; have each header mounted with the socket below the board and the pins sticking out the top. See this photo of the stack. | |
| + | | - | J5, J6, J8 | 0.1" pin headers | Buy in bulk | Headers; J5 and J6 are individual on each board if used, and J8 is only on the final board. | | ||
| | - | J10 | 0.1" dual row pin headers | Buy in bulk | Headers; J10 connects all boards together, so put sockets on one side of the boards and have the pins sticking through on the other sides. | | | - | J10 | 0.1" dual row pin headers | Buy in bulk | Headers; J10 connects all boards together, so put sockets on one side of the boards and have the pins sticking through on the other sides. | | ||
| | 1 | L1 | 10 uH inductor | 434-SMCCN-100K-02 | For LC filter for analog power rail | | | 1 | L1 | 10 uH inductor | 434-SMCCN-100K-02 | For LC filter for analog power rail | | ||
| Line 234: | Line 235: | ||
| 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. | ||
| + | |||
| + | (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 · Last modified: 2023/09/05 04:19 by sauraen
Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Noncommercial-Share Alike 4.0 International
