[Unofficial] Project Dream, Dreamcast 2.

Strictly SEGA related discussion.
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santefering
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Post by santefering »

I'm with you in that. I bought 2 second hand ps2 consoles and both died so not buying more. I think a dreamcast emulator exists on the PC. Just a shame they won't even make a knock off version.
Then again with all the petitions and fans we may very well get a new dreamcast system.
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Matty
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Post by Matty »

Going on experience & history the reason there are many Megadrive/Genesis knock offs are due to the Z80 processor being used in them originally & can be emulated/recreated very easily, many joke about the fact you're not a coder until you emulate the Z80 on a calculator. This leads on to why the sound is always crap as the Yamaha chip can't be recreated easily and they won't allow copies to be made afaik.

Relevance to the Dreamcast? I believe that the GD ROM technology that was used in the Dreamcast belongs to Yamaha & I can't see them being keen to let people have possession of the know how of that with it being the basis of the NAOMI arcade hardware (pretty old now) as well as the Tri-force (NintendoxSega arcade hardware) and the Chihiro (SegaxXbox) which may still be used to this day on lesser demanding titles.

That's why ATGames etc won't do a recreation in my eyes, just to name a few reasons aside from skimming over it above, The GD rom side, meaning it will have to be emulation based and not a hardware clone and that opens the door for piracy, The Dreamcast emulation isn't the greatest from what I remember & the emulator itself is Open source software, so no charging for the software itself.

Someone else may be able to go into more detail but that's all I can think for now and apologies if i've blabbed on for too long.
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Alpha Dog 1996
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Post by Alpha Dog 1996 »

I definitely have had trouble with systems before in buying used. I bought a used DS one time and the arrow keys refused to work. Thankfully I was able to refund it. I really do want a GameBoy Advanced though and so I'll have to eventually buy used again.
As for the Dreamcast emulator, I had one awhile ago for a game but I can't remember which game.
santefering wrote:I'm with you in that. I bought 2 second hand ps2 consoles and both died so not buying more. I think a dreamcast emulator exists on the PC. Just a shame they won't even make a knock off version.
Then again with all the petitions and fans we may very well get a new dreamcast system.
There can be only one Sonic! Metal Sonic is the real Sonic! Long live Metal Sonic!
Metal Sonic is the best! Death to all who oppose Metal Sonic! Metal Sonic rocks!


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santefering
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Post by santefering »

Matty wrote:Going on experience & history the reason there are many Megadrive/Genesis knock offs are due to the Z80 processor being used in them originally & can be emulated/recreated very easily, many joke about the fact you're not a coder until you emulate the Z80 on a calculator. This leads on to why the sound is always crap as the Yamaha chip can't be recreated easily and they won't allow copies to be made afaik.

Relevance to the Dreamcast? I believe that the GD ROM technology that was used in the Dreamcast belongs to Yamaha & I can't see them being keen to let people have possession of the know how of that with it being the basis of the NAOMI arcade hardware (pretty old now) as well as the Tri-force (NintendoxSega arcade hardware) and the Chihiro (SegaxXbox) which may still be used to this day on lesser demanding titles.

That's why ATGames etc won't do a recreation in my eyes, just to name a few reasons aside from skimming over it above, The GD rom side, meaning it will have to be emulation based and not a hardware clone and that opens the door for piracy, The Dreamcast emulation isn't the greatest from what I remember & the emulator itself is Open source software, so no charging for the software itself.

Someone else may be able to go into more detail but that's all I can think for now and apologies if i've blabbed on for too long.
You haven't blabbed too long, I'm grateful for the information as I didn't know much about how the system works. I'm aware of the sound chip though, after playing the awful music on a at@games megadrive it was horrible and tinny.
Hey is it true the megadrive one has better sound than the megadrive 2?
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Post by Midwinter »

santefering wrote:You haven't blabbed too long, I'm grateful for the information as I didn't know much about how the system works. I'm aware of the sound chip though, after playing the awful music on a at@games megadrive it was horrible and tinny.
Hey is it true the megadrive one has better sound than the megadrive 2?
I don't think this is the case, but I could be wrong. I only have version 2 and version 3 personally. I know they changed where the stereo output jack was from version 1 to version 2, but I think it is the same sound chip.
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Post by Quills on Wheels »

Yeah I dunno man. I'm almost 100% sure this will never happen. Sega already struggles enough with creating decent games, let alone get into the console industry again.
This team is very passionate. Can't deny it. I'm sure they'll present a pretty nice thing to Sega but even if they're allowed to present, hardly doubt it'll change any minds. I can't see any money in this investment for Sega and Sega's all about the money.
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Post by Matty »

santefering wrote:Hey is it true the megadrive one has better sound than the megadrive 2?
On the surface the difference between mark 1 & mark 2 is that mark 1 was stereo through the headphone jack only and mono everywhere else while the mk2 was stereo all the time (with no headphone jack). So arguably the mark 2 would be the better sound.

But to dig a bit deeper there are variations of the mark 1 console where some had a dedicated Yamaha sound chip and others had one built into a Sega branded chip (which was then carried on to the mark 2 I believe). The Sega one does have a few timing issues on some games, but the number of games can be counted on one hand and even then it's only a few milliseconds so not really noticeable.

And going even deeper some of the Yamaha chips had slight defects on them which caused a small buzzing noise on some games under certain conditions. Some of the security on later mark 1s can cause sound issues as well (something to do with an extra check on cartridges at boot) but I don't know enough of that to comment on it so will refrain from doing so.

So to summarise while a mark 1 with the original Yamaha chip will be what the sound was designed for, with the amount of hardware changes, number of chips with small faults and the fact it's only stereo on the headphone jack, your best choice is to go for a mark 2.
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Post by Whooa21 »

As Matty said, most Model 1s have a discrete YM2612 sound chip.
On Model 2s and a few 1s, they integrated the sound chip into a custom SEGA ASIC (Application Specific Integrated Circuit) in order to reduce costs.

The YM2612 used in the model 1 has an issue known as "ladder effect", producing some artifacts due to the way the waveform is generated. This issue is not present in the Model 2.
However, the Model 2 and a specific version of the Model 1 have a crap amplifier/mixer.

There are some hardware mods that bypass the model 2's audio circuitry, also known as "Crystal Clear sound" by TmEE.

However it is possible to fix the Model 1's ladder effect by disabling the outputs of the YM2612 chip while still using its timers for the Z80, and then using a YM3438 to produce output.
In other words, even though both chips are connected to the Z80 bus, it can only read from the YM2612 but write to both. And then with the use of some resistors and capacitors (because the 3438 is a CMOS chip), the output can be fed back to the Megadrive's amp.

In my case, I added a switch so that I can toggle between the two chips.

Here are two pictures of the mod.
https://vps.tasossah.com/misc/electroni ... 080235.JPG
https://vps.tasossah.com/misc/electronics/megadrive/P1080245.JPGAlso, I disagree that it is best to go with the model 2.
I would rather have some minor noises that can't really be noticed unless you are listening for them, than having bad sound in general because of the audio circuitry.

You can easily take a headphone jack to RCA cable and use that to output stereo to a TV.
So you get stereo audio from the front and the video from the back.

EDIT: For some reason I thought the model 2 was mono.
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Post by Twinny »

Radio:SEGA: Gang Since October 2010

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Midwinter
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Post by Midwinter »

Very interesting read. I still can't imagine this moving forward, but it shows the love Sega's last console has amongst people. It is amazing seeing Shenmue trend higher on Twitter and the outpouring of love for a series that was considered a huge financial failure back in the day. Maybe the Dreamcast will get a second chance too!
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