Retro Gen Adapter

[j_factor]

I could fix up the external circuitry, but I don't have the know-how to make a GOAC-based clone. At least, not yet. I'm currently in school specifically for that purpose: learn the ins and outs of electronic components to design the very best System-on-a-Chip clones you can get for both the NES and Genesis. My plan with said clones is to do this:

-Decap all the chips used in the NES and Genesis and take a good hard look at them (and a small FYI, my GOAC would have a YM2612 in it rather than a YM3438)
-Make the GOAC output RGB, S-Video and Composite
-Tweak the cloned 2C02 so it can output something better than Composite (hopefully Component)
-Make sure the clones are compatible with every game and add-on ever made (that includes the Sega CD for a GOAC-based Geniclone)
-Make sure the clones, especially the NES clone, work with flash carts (we all know how many NOAC-based clones just choke on the PowerPak and refuse to run it)

I'm thinking making these NOAC and GOAC designs on an FPGA then getting a custom ASIC put together might be a good way to get something like this into mass production. I'll tell you one thing though: there is no way in hell I'll outsource this to China. These clones are either to be made in Canada or the US. No exception.

Make a Game Gear clone while you're at it, please. kthx.

[Ace]

Aren't there some bugs in the YM2612 that are fixed in the YM3438?

That's specifically why I don't want the YM3438 in my own GOAC. The Genesis originally came with the YM2612, NOT the YM3438, and as such, I will stick to the YM2612.

Make a Game Gear clone while you're at it, please. kthx.

I'll remember that.

[j_factor]

I'll remember that.

In all seriousness, I would buy one in a heartbeat. Especially if it had video out.

[Ace]

Okay guys, it's time for the full review of the RetroGen Adapter.

Adapter

The adapter itself feels pretty solid. The plastic feels a touch cheap due to the textured plastic, but it still doesn't feel like it will break very easily. As the cartridge is shaped like a Super Famicom cartridge with indents on the back to fit in a Super NES, you can use the adapter on anything capable of playing Super NES games.

Video-wise, you're very limited as all you can get out of the box is Composite video. More on that in a bit.

The adapter itself has a 4-position region switch on the side with the settings labelled NTSC, PE, NJ, and PA. NTSC corresponds to NTSC English, PE to PAL English, NJ to NTSC Japan and PA to PAL Japan. I'll get into more details about this region switch later.

Pack-in accessories

The only thing you get with the RetroGen Adapter is a quite nasty A/V cable. Seriously, this thing is awful. It feels VERY cheap and is so highly prone to interference, I can't even hook up the RetroGen Adapter to my laptop without getting massive interference on the TV. The cable isn't even wired correctly! The left audio channel comes out the RED plug and the right audio channel out the WHITE plug. If you get a RetroGen Adapter, do yourself a favor and replace the A/V cables with some cables of higher quality.

Accuracy and A/V quality

Video-wise, this thing is surprising. Believe it or not, the video is BETTER than any Genesis Sega has ever produced, and I'm dead serious when I say this. the picture is very bright, the colors are very vivid (with a VERY slight hint of excess green), and the video is both sharper and has less edge pixellation than any Genesis. It's very good, HOWEVER, you should be careful where you use the adapter. Some TVs have sync issues with the RetroGen Adapter on white screens or brightly colored screens. It all depends on the TV. Some TVs take the video signal just fine such as my Electrohome 27E510 CRT TV, but other TVs might have screen tearing or complete loss of video sync. Keep that in mind.

Audio-wise, it's a bit of a mixed bag. It's passable, but other standalone Geniclones have better sound than this. It's a bit quiet, the bass isn't very strong, and the sound has a tendency to get a bit garbled and crunchy. Now, mind you, it's not as bad as some other Geniclones, but it's nothing exceptional. Still, it is perfectly listenable despite this crunchiness and slight difference in the volume level of some sounds produced by the YM3438. Speaking of volume level, the PSG is a bit too loud on the RetroGen Adapter. It doesn't have the potential to completely drown out the FM Synthesis unlike the RetroN3, but it's still noticeably louder than on a Genesis.

As the RetroGen Adapter has a Yamaha YM3438 within it, if you're used to the sound of the YM2612, you will notice the notes in some games will not last as long and in some others, notes will be considerably quieter than they would be if you were to use a Genesis with a YM2612.

Remember: as I previously mentioned, the Stereo sound is wired incorrectly on the A/V cables. The sound itself is not wired incorrectly on the A/V jack.

Also, if you use the RetroGen Adapter on a Super NES clone, you could use the audio outputs out of the clone instead of those on the RetroGen Adapter. I suggest you do this as the sound is generally better like this.

System compatibility

I've tested my RetroGen Adapter on the following systems:

-Super NES (SPC700 on a separate board)
-Super NES (SPC700 on the motherboard)
-Super NES Mini
-Super Famicom (SPC700 on a separate board)
-Super Famicom Jr.
-FC Twin
-RetroDuo v2.0
-FC3 Plus Version 1
-FC3 Plus Version 2

It works on all of them, even the two revisions of the FC3 Plus despite it being completely pointless. I will point out, however, that I've had problems with the RetroGen Adapter on my RetroDuo v2.0, though I'm pretty sure the problems have to do with the console itself and not the adapter as it works perfectly fine everywhere else. On the RetroDuo v2.0, the adapter works, but sometimes has phantom inputs on both the Start and Reset buttons (the game in the console resets itself on its own) and refuses to power up, and when it works, it doesn't register any inputs from any controller. Like I said, this is a problem with my RetroDuo v2.0 as the system itself seems to have a finicky Super NES cartridge slot.

Game compatibility

Here's a full list of what I've tested on the RetroGen Adapter:

Genesis:

-After Burner II: compatible
-Altered Beast: compatible
-Air Diver: compatible
-Ayrton Senna's Super Monaco GP II: compatible
-Bio Hazard Battle: compatible
-Blades of Vengeance: compatible
-Blockout: compatible
-Brett Hull Hockey '95: compatible
-Castlevania Bloodlines: compatible
-Contra Hard Corps: compatible
-Dr. Robotnik's Mean Bean Machine: compatible
-F1 Circus MD: compatible (this is a region-free Japanese MegaDrive cart, so region switch position doesn't matter)
-Ferrari Grand Prix Challenge: compatible
-Formula One: compatible
-Gaiares: compatible
-Galaxy Force II: compatible
-G-LOC Air Battle: compatible
-Golden Axe: compatible
-Gunstar Heroes: compatible
-Lotus II R.E.C.S.: compatible
-Mario Andretti Racing: compatible
-MIG-29 Fighter Pilot: compatible
-Newman-Hass IndyCar Featuring Nigel Mansell: compatible
-NHL 96: compatible
-Nigel Mansell's World Championship Racing: compatible
-OutRun 2019: compatible
-Road Rash: compatible
-Road Rash II: compatible
-Road Rash 3: compatible
-Rolling Thunder 2: compatible
-Rolling Thunder 3: compatible
-Sagaia/Darius II: compatible
-Sonic the Hedgehog (US version): compatible
-Sonic the Hedgehog (Japanese version): compatible
-Sonic the Hedgehog (European version): compatible (do not use any of the PAL settings or the game will have graphical glitches)
-Sonic 2: compatible
-Sonic 3: compatible
-Sonic Spinball: compatible
-Sonic 3D Blast: compatible
-Sonic & Knuckles: compatible
-Sonic the Hedgehog locked onto Sonic & Knuckles (Blue Sphere): compatible
-Sonic 2 locked onto Sonic & Knuckles: INCOMPATIBLE (black screen - WTF?)
-Sonic 3 locked onto Sonic & Knuckles: compatible
-Space Harrier II: compatible
-Sub-Terrania: compatible
-Super Hang-On: compatible
-Super Monaco GP: compatible
-Super Off-Road: compatible
-Super Street Fighter II: compatible but glitched (some PCM samples come out as loud garbage)
-Super Thunder Blade: compatible
-Thunder Force II MD: compatible
-Thunder Force III: compatible
-Thunder Force IV/Lightening Force: compatible
-Thunder Fox: compatible
-Top Gear 2: compatible
-Twin Cobra: compatible
-Universal Soldier: compatible
-Virtua Racing: INCOMPATIBLE (black screen)
-Whip Rush: compatible

-Sega CD: INCOMPATIBLE (duh)
-Sega 32X: INCOMPATIBLE (duh)
-Sega Master System converters: compatible

Master System games:

-Ace of Aces: compatible
-After Burner: compatible (depending on your RetroGen Adapter and Master System converter, you may need to hit the Reset button before the game will boot)
-Double Dragon: compatible
-Galaxy Force: compatible
-Global Defense: questionable (seems it works only on some RetroGen Adapter/Master System converter combinations)
-Hang-On/Safari Hunt: semi-compatible (Hang-On works but Safari Hunt is unplayable due to the inability to plug in a Light Phaser)
-OutRun: compatible
-R-Type: compatible
-Sonic the Hedgehog (European version): compatible
-Space Harrier: compatible
-Space Harrier 3D: compatible (3D glasses should work too if your Master System converter has a card slot)
-Thunder Blade: compatible

No Genesis or Master System accessories will work with the RetroGen Adapter.

While Virtua Racing being incompatible was expected, Sonic 2 + Sonic & Knuckles being incompatible as well as the sound glitches in Super Street Fighter II are mind-boggling, especially considering the RetroN3 runs on IDENTICAL hardware and has no problems playing either game. We'll have to investigate this a little more closely.

A word of note on Master System games: many of the bigger games experience varying degrees of graphical garbage on the screen. It's not game-breaking, but it's very distracting regardless. BUT, I don't know if this is just a problem with my converter or the RetroGen Adapter, but when I play Master System games, it looks like the system is experiencing electrical problems as I get some thick flickering horizontal lines on the screen and MAJOR video and electrical noise in the audio signal. Someone with an actual Power Base Converter and a RetroGen Adapter would have to report back so I can confirm what causes this problem.

You also cannot use a Konami Justifier to play Safari Hunt. It doesn't work.

Another note concerning the region switch: even though you set the RetroGen Adapter to any of the PAL settings, it will still work in NTSC. Some games may have graphical garbage at the top of the screen with the region switch set to PE or PA. Even a PAL version of Sonic the Hedgehog has this problem, so running PAL games on the RetroGen Adapter may be a bit of a problem

And that's the RetroGen Adapter. Next up is the teardown of the adapter. We're going to take a good look at what makes the RetroGen Adapter work.

[SEGA.GENESIS1989]

That was a pretty detailed analysis. How much does this thing retail for at the moment?

[KnightWarrior]

$24.99

[SEGA.GENESIS1989]

Thanks. Considering it's shortcomings, that sounds like a fair price for the device.

[KnightWarrior]

I can't wait til the teardown on the the RetroGen how it works....

[Ace]

Teardown time! Let's have a look at the RetroGen Adapter.

Here's the front of the PCB:



Each number corresponds to a different chip as follows:

1) TCT-6801 - This is the GOAC at the heart of the RetroGen Adapter. Contains all the hardware found in the Genesis within it. Same GOAC as the RetroN3.
2) Winbond W29C020 - A 2MBit Flash ROM. I'm curious to know what this ROM contains. Something to do with the button mapping or a boot ROM, perhaps?
3) TA153A - Have no idea what these chips are. I can't find any information on them, though I do assume they have something to do with the circuitry used to send controller inputs into the GOAC.
4) 74HC595 - These are 8-bit shift registers. Some of these seem to be linked to the TA153As, so they may have something to do with the controller circuitry.
5) 74HC138 - This is a 3-to-8 decoder. Appears linked to at least one of the 74HC595s. May be related to the controller circuitry as well.
6) A mystery IC hidden within an epoxy blob. Purpose is unknown.

Here's the back of the PCB:



There's a single chip on here, which is a 74HC74D, a dual D-type flip-flop. It again seems to be related to the controller circuitry as it's linked to the 74HC138.

Mods on this thing don't seem very easy. Adding in TmEE's Audio Mod is out of the question as there is very little space for you to work with. The video circuitry is fine as-is minus the sync issues, so the video signal may need to be weakened. The only thing really in need of fixing is sound, and it MAY be possible to add 2 Genesis controller ports to the adapter. You would need to find the controller inputs on the GOAC and wire up two DB9s to the adapter.

Here's one thing I'd like to do: figure out how to mix the video signal from the RetroGen Adapter into consoles where you have to use the supplied A/V cables. I think the video output of the Super NES (clone) would need to be cut off when the RetroGen Adapter is plugged into the console. Anyone have any insight on this?

[KnightWarrior]

Anything yet Ace?

[Ace]

Well one thing's for sure: Virtua Racing compatibility on this thing is still a definite NO. It also seems !CE_H either doesn't work right or works in a weird way as I tried to tie it permanently high and permanently low on a VA2 Genesis Model 2 I have in which I might stick in a YM3438, and in both cases, Virtua Racing showed the TMSS screen, then crashed. It's possible the cartridge slot is too dirty as games have a bit of a hard time to boot, but I will give this a shot some other time. In the meantime, if anyone wants to have a go at this, get a Genesis you don't particularly care for and cut the trace leading to pin B26 of the cartridge slot, solder the pin itself to pin B16 of the cartridge slot, and finally, solder the trace you just cut first to VCC, then to Ground. Report back on what happens.

All work has been stalled on the RetroGen Adapter as I'm in the middle of putting together a new shelf for my new gaming setup. Once I'm done, I'm going to start recording capture footage for RetroGen Adapter vs. Original Hardware, post those videos on YouTube, then progressively put the links to those videos in this thread.

Which leads me to this question: on what console should I use the RetroGen Adapter on? I'm thinking of using it in either of these:

-Super NES (SPC700 on a separate board)
-Super Famicom
-Super NES Mini
-Super Famicom Jr.
-FC Twin

The adapter works the same way on all 5 consoles, BUT on the FC Twin, if you hook up the audio outputs from the console and not from the RetroGen Adapter, you can hear slightly more muffled, but louder audio (I personally wouldn't record the sound coming out of the FC Twin as it's different from that of the RetroGen Adapter). On original hardware, you get complete silence.

[KnightWarrior]

Well I'm going to get one in a couple month...

If you have an Retro Duo try it out on that..Make sure all the contact are super clean, even Virtua Racing,

I can't really get one, as I found out I have to save for Vegas in July..After Vegas yes....

[TrekkiesUnite118]

That's specifically why I don't want the YM3438 in my own GOAC. The Genesis originally came with the YM2612, NOT the YM3438, and as such, I will stick to the YM2612.

Are any games actually made to make use of those bugs? If not I'd say the fixed bugs is fine as that's probably what was intended to be heard. You don't make hardware intending there to be bugs and saying "that's how it should be!"

[Ace]

Well I'm going to get one in a couple month...

If you have an Retro Duo try it out on that..Make sure all the contact are super clean, even Virtua Racing,

I can't really get one, as I found out I have to save for Vegas in July..After Vegas yes....

My RetroDuo still has issues with the RetroGen Adapter, but that's because the console itself has a very loose Super NES slot. It should work, though, except since I loosened the cartridge slot on my RetroDuo a bit too much, it doesn't work very well, and when it does work, controllers are 100% unresponsive.

Are any games actually made to make use of those bugs? If not I'd say the fixed bugs is fine as that's probably what was intended to be heard. You don't make hardware intending there to be bugs and saying "that's how it should be!"

Take a listen to After Burner II on a Genesis with a YM2612, then listen to the music on a Genesis with a YM3438. There's a big difference between the two (it's just one example, but it's my favorite to use as After Burner II makes the YM3438's bugfixed DAC very apparent).

But the hardware is what it is, not what it "should have been".

Hence the reason why if I were to make a GOAC, I'd integrate the YM2612 rather than the YM3438.

[KnightWarrior]

Go for the SNES insted

Again, Who's idea was it to put TCT-6801 in the RetroGen??