OPNA for MSX - Anyone working on one to market & interest?

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By syn

Paragon (1862)

syn's picture

12-03-2018, 01:12

Could be pulls from used/defect old hardware like arcade boards. And opl4 might be more expensive in general (more channels etc) although i dont have info regarding that

By Pencioner

Hero (647)

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12-03-2018, 01:28

I don't remember exactly but the price was around $30 for OPL4 (not used, not fake) on ebay. I bought one for homebrew Wozblaster in 2015

By Grauw

Enlighted (7356)

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12-03-2018, 09:56

OPNA’s ADPCM is near identical to the MSX-AUDIO’s, so it should be possible, but I tried once to do it quickly and it didn’t work so it needs some further investigation. But still the six PCM drums are not emulated then... I suppose I could play those with the OPL4, but... yeah, it becomes quite a stack of sound chips you need then. Not a priority for me, I’d rather encourage OPNA hardware development for proper playback Smile.

I bought four OPNAs from an eBay seller a few years back, one of which is on the OPNA board I got from Leonard, and all four of them are real. (Even though their surface looked a bit dodgy so I was suspicious after I got them.)

By -Neo-

Champion (364)

-Neo-'s picture

12-03-2018, 18:19

Maybe Leonard will join in and be willing to produce a OPNA cartridge for those interested. Or in case he can't maybe share board design so someone else is able to produce it.

7 showed interest till now, differing on the amount of interest. If it would help development I would even buy 2 Smile

By l_oliveira

Hero (518)

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26-03-2018, 23:35

Hey guys seems like Supersoniqs will be making some OPN carts for everyone:

https://twitter.com/supersoniqs/status/977873641797910528

By syn

Paragon (1862)

syn's picture

26-03-2018, 23:55

hurray ! Big smile

By alexito

Master (215)

alexito's picture

27-03-2018, 04:26

I'm In. Thanks Sander and the Playsoniqs Team.

By Alexey

Guardian (1613)

Alexey's picture

27-03-2018, 11:59

Nice! Will the cartridge be sold in a case or just as a board? Will there be kits available for self-assembly or maybe just bare boards? Any idea about the approximate price?

By ImATrackMan

Expert (67)

ImATrackMan's picture

01-06-2018, 11:22

While an OPN cartridge is indeed cool, it doesn’t negate the desire for an OPNA cartridge, especially if the cart doesn’t even use an OPN. I made this comment as a reply to the original post but didn’t get very far with a solid response.

Using OPNB would mean throwing away half of the chip’s features. The OPNA has SSG (identical to the internal PSG of our computers), 6x 4-operator FM identical to the OPN2 and SIMILAR to the OPM/OPP in the SFGs (no other MSX FM chips could come close to emulating it as all of them are 2-operator), 1x ADPCM SIMILAR to MSX-AUDIO ADPCM and 6x Rhythm channels that are nothing like the ones on the OPLL, MSX-AUDIO, or OPL4 (OPLx RHY is FM-based, OPNA RHY is ADPCM samples in a ROM.

To emulate most of the capabilities of the OPNA on existing chips, you’d need your MSX for SSG, the SFG for the FM (and it wouldn’t even be a complete emulation), MSX-AUDIO or a Turbo-R for the ADPCM, and an OPL4 for the RHY samples, AND you’d still need to correct for frequency since the OPNA SSG and FM can be set to different clock speeds in software. It’s not worth it at all.

The OPNB on the SuperSoniqs cart is on one hand similar to the OPNA, but on the other hand, totally useless for OPNA.
It has all of the components, SSG, FM, ADPCM type A (Rhythm), ADPCM type B (single-channel ADPCM). This is all well and good, BUT it only offers 4 FM channels, there is ZERO support for external ADPCM RAM, and the RHY ADPCM channels are no longer internal. Yes that means more external samples, but that means any music using the OPNA rhythm sounds will have no drums unless they’re loaded from an external ROM. Effectively, you lose two FM channels and all drum sounds.

On the other hand, OPN just has 3 FM channels and 3 SSG channels, which is (almost) PERFECTLY emulable (emulatable?) on the SFG. With some coding hackery, it MIGHT even be possible to support the CH3 extended mode as it would only use a max of 6 OPM channels, and the only feature missing would be the SSG-EG feature on the FM. Using an OPNB wastes half of the features of the chip, while still leaving it useless for OPNA.

Using an OPNA cart however, you can play back OPN with no changes to anything, and you can use all OPNA features. This has had me excited for so long, I’m even starting to get into talks with people to port the popular PMD sound driver for PC-88 and PC-98 to MSX (which also supports OPM and OPL). I’d even learn MML specifically for this (and I hate MML).

Basically what I’m saying is: OPNA is the only way to properly do OPNA. Nothing already on MSX can easly replicate what this one chip can do on its own.

By Grauw

Enlighted (7356)

Grauw's picture

01-06-2018, 11:31

ImATrackMan wrote:

The OPNB on the SuperSoniqs cart is on one hand similar to the OPNA, but on the other hand, totally useless for OPNA. It has all of the components, SSG, FM, ADPCM type A (Rhythm), ADPCM type B (single-channel ADPCM). This is all well and good, BUT it only offers 4 FM channels, there is ZERO support for external ADPCM RAM, and the RHY ADPCM channels are no longer internal.

There’s the YM2610B (OPNB-B) which does have 6 channels, I think SuperSoniqs intends to use this? Also surely ADPCM data can be uploaded otherwise such a strongly PCM-based chip wouldn’t be very useful. Indeed the OPNB does not provide a RAM access interface, so this needs to happen through external circuitry. The RHY channel sample set can be loaded automatically by the player, the PCM data could even be in a ROM on the cartridge so that players don’t need to contain the sample set themselves.

But an OPNA cart is also neat, of course, and easier to make.

ImATrackMan wrote:

On the other hand, OPN just has 3 FM channels and 3 SSG channels, which is (almost) PERFECTLY emulable (emulatable?) on the SFG. With some coding hackery, it MIGHT even be possible to support the CH3 extended mode as it would only use a max of 6 OPM channels, and the only feature missing would be the SSG-EG feature on the FM.

VGMPlay does play all 6 OPNA channels on SFG, but there’s no samples support of course.

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