Carnivore 2 and FC-200

By MrSiggler

Supporter (5)

MrSiggler's picture

17-11-2022, 14:38

Hey all!

I recently started down the road of building myself an Omega, as well as a Carnivore 2 to use in it. I've got the Carnivore 2 built now, and have been testing it out in an FC-200 MSX1. I have a few questions about the audio I'm getting out of it.

First off, I piggy backed some 1.2Kohm resistors to the pair of resistors on the FC-200 board to fix the slot audio.

My issue, is that the levels between the PSG and SCC/FM are very odd. With the default carn volume level of 4/4/4 I can barely hear the PSG(if at all), the SCC/FM completely overpower it. To get the music to sound anything like what I hear on various youtube videos of these songs/games, I need to lower the SCC/FM to 1 or 2, and crank the PSG to 7 or 8. And this is when I listen via the jack on top of the cartridge to the line in of my computer.

If I listen to the audio from the rear jack, it's the opposite problem. The PSG is far too loud, and I can barely hear the SCC/FM.

This is all with the PSG and Clicker enabled in the carn config, but not dual-psg.

Any suggestions/thoughts? Is this normal for the audio coming from the Carnivore 2? Could it be an issue with the FC-200? (I did have to do that mod to get any audio out of the Carn at all, etc)

Thanks!

Login or register to post comments

By djh1697

Paragon (1694)

djh1697's picture

17-11-2022, 17:11

This was an issue with the FC200, the "soundin" pin on the cartridge port is at the incorrect level.

I think you can set the C2 to disable the PSG and use the C2's PSG instead, this would solve the issue.
https://sysadminmosaic.ru/en/msx/carnivore2/carnivore2#sound_settings

By djh1697

Paragon (1694)

djh1697's picture

17-11-2022, 17:13

The C2 is a very capable device, I use mine all the time when I am using my MSX, I also have an MFRSCC+SD, the latter does not give you as much control regarding the sound chips.

By sdsnatcher73

Prophet (3799)

sdsnatcher73's picture

17-11-2022, 18:34

Still what you describe seems odd. The 3.5mm out should provide balanced mix. Maybe somehow the FC200 is feeding sound into the C2 through it’s SNDIN pin? This is against specification but if the audio circuit is designed badly it may still happen, also C2 probably has no protection against such a situation.

By MrSiggler

Supporter (5)

MrSiggler's picture

17-11-2022, 18:47

There is a bit of that. When I have the PSG emulation turned off on the Carnivore, and start playing music, I *can* hear the PSG coming back up into the Carn's 3.5mm from the MSX's own audio, but it's very, very quiet.

One other thing, (I meant to ask about this in my original post, actually), but if I plug headphones into that 3.5mm jack, the audio from the MSX's own audio port cuts out, and gets a little garbled. But plugging a 3.5mm audio cable between the Carnivore and my PC, the MSX audio port is unaffected. Is this normal?

Thanks again!