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Genesis 1 Stereo mod

Started by Richter X, May 20, 2007, 06:03:49 AM

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Richter X

I just bought myself a Sega Genesis Model 1, this time it has all the connections (RF Switch & AC Adaptor) unlike my Model 2. Unfornately, all the Model 1s I've ever used never look or sound as good as the Model 2s as the Model 1's video from RF looks dirty (it IS RF after all) and the audio doesn't sound too great either on the TV or through the headphone jack (sounds slightly distorted, especially on high frequencies).

I was just wondering if these problems would go away if I used the AV out instead of the RF switch, and if I could modify the Model 1 to have Stereo RCA jacks in the back so I could play the stereo output on the TV instead of just the headphones. I've seen the mod done before. And would I have to worry about anything once I get my Sega CD?

blackevilweredragon

May 20, 2007, 06:39:46 AM #1 Last Edit: May 20, 2007, 06:41:06 AM by blackevilweredragon
You'll need to do what I did..  I removed the RF box out of mine, and mounted a mini din-9 connector inside my Genesis..  with that, I then connected all the appropriate wires to where the DIN-8 sat (i also removed that)..  I grabbed the audio from the headphone jack's pins....  works great...

For Genesis sounds on the Sega CD, if you do that route, you'll need a mixing cable..  or better yet, go to radio shack, get a headphone-to-headphone wire..  not an extension, but the cable that has the male plug on both ends (STEREO)..  then set the volume to 7-8, and your set..

Richter X

Would I still have to use the mixing cable with my Model 2 Genesis? Or would I just need to use the Stereo AV cable?

kendrick

When a Sega CD is connected to a Genesis 2, the bus connector is where the audio signals are transmitted. The idea is that the Sega CD doesn't receive those from the Genesis 1 because the pins aren't present, and so has to get that externally from the headphone jack. Unless your mod also replaces those missing pins, you're probably required to have the mixing cable still.

-KKC

Richter X

I just got an idea. What if you took the 9-pin connector from the inside of a Genesis 2 and modded it into the Genesis 1 to replace the larger AV port, making sure to take the stereo audio from inside and connecting it to the stereo pins in the connector?

blackevilweredragon

May 20, 2007, 07:58:07 AM #5 Last Edit: May 20, 2007, 07:58:52 AM by blackevilweredragon
QuoteI just got an idea. What if you took the 9-pin connector from the inside of a Genesis 2 and modded it into the Genesis 1 to replace the larger AV port, making sure to take the stereo audio from inside and connecting it to the stereo pins in the connector?
that's exactly what i just said..  but you can't just "drop" it in, the pins are in different locations, they don't line up..  you have to wire it to them..

Richter X

Found the mods I was talking about. How in the world would you do these?

Various Sega Genesis Mods

blackevilweredragon

QuoteFound the mods I was talking about. How in the world would you do these?

Various Sega Genesis Mods
Once again, read what I had already said.

You can grab the stereo sound from the Headphone jacks pins, and put the RCA jacks on it...

Lost Monkey

In the Gen 1, the non-amplified,  separate audio signals can be found on pins 1 and 8 of the CXA1034... If you tap it at these points rather than at the headphone jack, you will eliminate the distortion caused by the volume slider...

Richter X

QuoteIn the Gen 1, the non-amplified,  separate audio signals can be found on pins 1 and 8 of the CXA1034... If you tap it at these points rather than at the headphone jack, you will eliminate the distortion caused by the volume slider...
I'll have to give that a try sometime. It's 1 and 8 on this schematic, right?

Lost Monkey

Quote
QuoteIn the Gen 1, the non-amplified,  separate audio signals can be found on pins 1 and 8 of the CXA1034... If you tap it at these points rather than at the headphone jack, you will eliminate the distortion caused by the volume slider...
I'll have to give that a try sometime. It's 1 and 8 on this schematic, right?
That's right.

blackevilweredragon

QuoteIn the Gen 1, the non-amplified,  separate audio signals can be found on pins 1 and 8 of the CXA1034... If you tap it at these points rather than at the headphone jack, you will eliminate the distortion caused by the volume slider...
tried it..  it's VERY weak, so weak that actually trying to use them causes problems..

Richter X

Is there at least a way where you can replace the crappy amp with a better one?

blackevilweredragon

don't know, that's beyond my scope (micro audio amps)..

Richter X

When I opened up my Genesis 1 (for some reason there as a large wall screw inside of it!), it looked nothing like the schematic. For example, I didn't even see a YM2612 chip! And in the place of where that amp chip is supposed to be (right next to the power switch) there's two tiny chips and about 3 tiny circles of some copper coil. My Genesis also lacks the EXT connector that's usually next to the RF Switch port. Plus there's only one voltage regulator next to the AV port instead of the two that's usually there. Now I'm really confused. :blink:  

blackevilweredragon

QuoteWhen I opened up my Genesis 1 (for some reason there as a large wall screw inside of it!), it looked nothing like the schematic. For example, I didn't even see a YM2612 chip! And in the place of where that amp chip is supposed to be (right next to the power switch) there's two tiny chips and about 3 tiny circles of some copper coil. My Genesis also lacks the EXT connector that's usually next to the RF Switch port. Plus there's only one voltage regulator next to the AV port instead of the two that's usually there. Now I'm really confused. :blink:
you mean this one?   http://img.photobucket.com/albums/v395/Evi...on/latemd12.jpg


that's the LATE model, right before the switch to model 2...  just do what I said, and GET THE HEADPHONE PINs...

Richter X

Yep, that's the one. I'll give it a try. The current headphone output sounds pretty lousy (and fuzzy), though. If I connect it through the pins, will it sound any better?

blackevilweredragon

QuoteYep, that's the one. I'll give it a try. The current headphone output sounds pretty lousy (and fuzzy), though. If I connect it through the pins, will it sound any better?
Since you hear the audio problem, I need to be honest with you.  That generation of Genesis models suffered from a VERY shitty audio amplifier, just like the Model 2 Genesis systems (remember, this late model 1 and model 2 share a LOT)...

you'd need to do serious re-wiring (messing with the circuit) to get any better audio out of it..  there exists a mod to model 2's, which honestly make the audio EXTREMELY awesome, topping CD-Quality..  It "might" work with the late model 1, but it's not known yet..

Richter X

Sounds very interesting. I'll have a listen from my Model 2 once I get all the cables for it in a few days to see if it sounds any better/worse. If it sounds as bad, how would I mod it to make it sound excellent as you described?

blackevilweredragon

QuoteSounds very interesting. I'll have a listen from my Model 2 once I get all the cables for it in a few days to see if it sounds any better/worse. If it sounds as bad, how would I mod it to make it sound excellent as you described?
if you feel it sounds as bad, i'll get instructions from a friend who's done the mod..   (or have him post here)

eastx

I'd like to know of this mod too. We really need to have all the mods for a system collected in one location... I'm always hearing about this-or-that-mod that sounds cool, but I can't find the instructions. That's no good!

Richter X

Just got my Stereo AV cable in today. Good god does the Model 2 sound awful! Also, there's transparent rows of vertical lines on the screen for some reason. Never get that with the model 1's RF Switch. >_>'

Richter X

Anyways, what's the mod? I really need to fix it. I'd also like to fix the Vertical lines, but I'm guessing that's something only RGB can fix.

Asaki

December 03, 2007, 08:15:27 AM #23 Last Edit: December 03, 2007, 08:19:05 AM by Asaki
Quote from: blackevilweredragon on May 26, 2007, 01:15:58 PMthere exists a mod to model 2's, which honestly make the audio EXTREMELY awesome, topping CD-Quality..

So Gen 2 has both a video and a sound problem that I haven't noticed? ???

Where can I find links to these? I did a few searches and can't find crap.

Richter X


Asaki

December 13, 2007, 04:24:39 AM #25 Last Edit: December 13, 2007, 04:26:56 AM by Asaki
Wow, no wonder I never noticed it...I was expecting it to be scratchy or something, not muffled like that.

Too bad they didn't use a common game like Sonic in the examples so we could all get a really good comparison.

Might have to try this mod out on my spare Genny sometime (assuming that the PAL mod works the same on an NTSC)...if I can ever find that "fix lines" mod. Of course, both of my Gennies (Genii?) have different boards, so that doesn't help either.

phreak97

Quote from: eastx on May 29, 2007, 10:48:53 AM
I'd like to know of this mod too. We really need to have all the mods for a system collected in one location... I'm always hearing about this-or-that-mod that sounds cool, but I can't find the instructions. That's no good!


wiki it up!

arfgh

Hey guys,

i am thinking if is possible to use the MegaDrive model 1 Din-8 connector to send the stereo audio from the pins 1 and 8 of the said IC to the 32X console. The idea is related to the building of the 32X RGB cable that can be connected to stereo audio pins of the Euro-Connector.

The MegaDrive model 1 dont pass any sound to these Euro-Connector pins because the audio mono is passed from the "audio mono" pin of the Din-8 and the 32x mini din-9 have also this audio mono pin that must be wired to get the mono sound.

The thing is if we can build this mod and make the cable that connects the MegaDrive to the 32x, to send the stereo audio.

What you think about ?

localheureux

Quote from: Richter X on May 20, 2007, 12:23:39 PM
Found the mods I was talking about. How in the world would you do these?

Various Sega Genesis Mods

Dead link, is there another valid adress?


Quote from: Richter X on May 20, 2007, 04:24:09 PM
QuoteIn the Gen 1, the non-amplified,  separate audio signals can be found on pins 1 and 8 of the CXA1034... If you tap it at these points rather than at the headphone jack, you will eliminate the distortion caused by the volume slider...
I'll have to give that a try sometime. It's 1 and 8 on this schematic, right?

Very interesting, but I don't understand one thing.
What does means exactly "EQoA,EQiA/EQoB,EQiB" on the IC CXA-1034?


Thanks

Drakon

Quote from: Richter X on May 20, 2007, 06:03:49 AM
I just bought myself a Sega Genesis Model 1, this time it has all the connections (RF Switch & AC Adaptor) unlike my Model 2. Unfornately, all the Model 1s I've ever used never look or sound as good as the Model 2s as the Model 1's video from RF looks dirty (it IS RF after all) and the audio doesn't sound too great either on the TV or through the headphone jack (sounds slightly distorted, especially on high frequencies).

I was just wondering if these problems would go away if I used the AV out instead of the RF switch, and if I could modify the Model 1 to have Stereo RCA jacks in the back so I could play the stereo output on the TV instead of just the headphones. I've seen the mod done before. And would I have to worry about anything once I get my Sega CD?

I hooked up a model 2 through rgb to s-video and using stereo sound from the port at the back.  Then I hooked up my Japanese model 1 through rgb to s-video getting stereo sound from the headphone jack.  This is the first japanese revision of the model 1 with the ext port on the back.  The model 2 I used was just a regulat us model 2.  Obviously both systems had equally good looking picture.  But my Japanese model 1 sounds WAY better than my us model 2.  Both using stereo sound without any system modifications