Search found 92 matches
- Sun Jun 22, 2014 10:34 am
- Forum: Hardware
- Topic: Check my ac adaptor
- Replies: 5
- Views: 6105
The only way to check to see if they can provide the rated current is to connect them to the rated load. The tool to do this is called a "dummy load" or sometimes (paradoxically) a "load generator". It's effectively a series of resistors, and that's basically the same thing as an electric heater. Yo...
- Fri May 16, 2014 6:28 am
- Forum: Megadrive/Genesis
- Topic: Sega Mega Drive/Genesis Collected Works
- Replies: 18
- Views: 16789
- Thu May 01, 2014 4:22 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
- Sat Apr 26, 2014 6:26 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
The chip doesn't mind a voltage divider if you use it *after* the coupling cap that removes the DC component, so you can use that technique to reduce the signal to something the amp can handle. I have to do this for the lm386es, you can see it at the 12k<->220k divider after each of C30 through C33....
- Sat Apr 26, 2014 3:01 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
Haha, well, I took a scope to it today and found out that it was clipping the bottom half of the audio not the top half - the elimination of the 12k pulldown resistor that the YM2612 needs and the elimination of the 10uf cap are the only changes necessary to support the ym3438. I did find out someth...
- Wed Apr 23, 2014 8:16 pm
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
Sweet! Thanks, guys. I'll come up with something. @Aly, I'll send you a device with one YM2612 and one YM3438 when I get it ready, and I'll update the board layout to have selectable voltage dividers. Automatically detecting the YM3438 will probably be too much for me, so we're gonna have to use a s...
- Wed Apr 23, 2014 10:01 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
- Wed Apr 23, 2014 3:28 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
Today I got my YM3438 chips in, which will require a hardware change to support. It's definitely much louder than the YM2612 and might require a voltage divider at the coupling capacitor. It's definitely clipping. I should be able to figure out how to fix it with a scope and I remember reading somew...
- Fri Apr 18, 2014 5:02 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
First prototype assembled and fully functional!
YouTube: https://www.youtube.com/watch?v=sqC9TVTOV_M
YouTube: https://www.youtube.com/watch?v=sqC9TVTOV_M
- Tue Apr 15, 2014 10:23 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
@gigasoft: 12-tone polyphony is a goal of this project. It's probably the default mode that you'll use when playing over MIDI, although the option to switch to one MIDI channel per channel will be selectable. This is fairly easy to do and in fact there is already code that does it. The workflow I've...
- Tue Apr 15, 2014 5:28 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
- Tue Apr 15, 2014 3:13 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
Aah, ok. That's interesting. I'll figure that out later and get it to work. I got the first run of boards in today and started assembling them! I'm still waiting for some parts to come in from Digikey so I can't do anything big yet. But I did power up the Teensy and make sure there are no shorts on ...
- Thu Apr 10, 2014 5:34 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
- Thu Apr 10, 2014 5:24 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
sure! I kind of halfassed the recording with a usb capture thing, but it shouldn't matter much since the thing is still just on a breadboard anyway. Took a picture too ;) saved it as a huge flac file so it sounds as close as possible to the original output http://7355608.net/alyrecording.jpg http://...
- Tue Apr 08, 2014 4:58 am
- Forum: Sound
- Topic: Dual-YM2612 hardware synthesizer
- Replies: 53
- Views: 69864
The deal is that to playback audio via the DAC, a VGM file records the transactions on the bus between the Z80 and the ym2612. A VGM also contains a recording of the time that the z80 spins in a tight loop waiting for the next instruction. In order to play back the vgm file, you need to act on each ...