Famicom World

Misc. => Other Gaming => Topic started by: keiffer01 on August 22, 2007, 07:28:03 pm

Title: NES stereo output mod
Post by: keiffer01 on August 22, 2007, 07:28:03 pm
I always wanted to mod my NES system so it could output real stereo, but I can't seem to find any guide on the net on how to perform this. There is only one guy I found on the net who did this, but he doesn't give enough details on how to do it and he doesn't have enough pics of the mod. Does anyone here on Famicom World have the knowledge or has already performed this on their NES and would be ready to help me out and maybe send some pics? Thanks! ;D
Title: Re: NES stereo output mod
Post by: 133MHz on August 22, 2007, 07:42:09 pm
Check here (http://www.raphnet.net/electronique/nes_mod/nes_mod_en.php). Never tried it but looks better than just tapping from the CPU pins.
Title: Re: NES stereo output mod
Post by: keiffer01 on August 22, 2007, 08:05:06 pm
That's the guy I was talking about! ;D I find that he doesn't show enough pics and some of his pics are somewhat hard to see where the wires are connected. I'm not a proffessional at reading schematics (I'm only 14! ;D) so this is really the reason to why I wanted more pics of how this is done. With some better pics I would be able to do this without a problem. :)
Title: Re: NES stereo output mod
Post by: 133MHz on August 22, 2007, 08:11:59 pm
Oh I understand. The pics are not very good at showing, but I saw the schematic and it's very straightforward. Feel free to ask what you don't understand of it ;).

Note: This mod seems very good and actually I think that it would sound way better with the ability to mix back some of the mono sound onto the stereo channels (like real stereo instead of just two channels into one speaker and three channels into the another). I would do it, but I don't feel like punching more holes into my NES ;D (the only hole I made is for installing the speed switch, and that's in a way not to ruin the aesthetics).
Title: Re: NES stereo output mod
Post by: keiffer01 on August 22, 2007, 09:00:57 pm
I'm mixed up with the wires places. Three wires seem to be connected to the CPU pins; a red wire on the top part of the first pin, and two yellow wires on the top and bottom part of the second pin, all  held together in a shielded cable. So are all the three wires then connected to one of the RCA jacks together? And that green wire connected to the power supply, RF modulator and RCA Mono audio/video output module, is it connected directly to the other RCA jack, or is it connected to one of the 3 other wires? I'm all mixed up! :D
Title: Re: NES stereo output mod
Post by: 133MHz on August 22, 2007, 09:40:04 pm
And you mixed me up too ;D. Better don't trust the pictures and follow the schematic ;).
Title: Re: NES stereo output mod
Post by: keiffer01 on August 22, 2007, 09:52:30 pm
Yeah I know but I have trouble reading one ;D My dad knows how to read them but he says the guy seems to be missing some details. But my dad is a really lazy guy when it comes to help me out in electronics and games. Sometimes I need to help him and all when he needs help with his things but when it comes to my things he doesn't really care at all! :-\ Sometimes I'm trying to fix some game system that could be fixed, and as soon as I ask him some help he always says there's no way to fix it and just gives up. But when it comes to his things he takes all his time and repairs them neatly with love and care. Well I guess it's like that with everyone. ;)
Title: Re: NES stereo output mod
Post by: 133MHz on August 22, 2007, 10:04:33 pm
As I said before, feel free to ask me what causes you problems with the schematic and I'll help you out ;).
Title: Re: NES stereo output mod
Post by: keiffer01 on August 24, 2007, 12:50:08 pm
To what is the green wire connected to? An RCA jack?
Title: Re: NES stereo output mod
Post by: 133MHz on August 24, 2007, 05:35:39 pm
It's going to the 'Mono audio' output on the schematic.
Title: Re: NES stereo output mod
Post by: keiffer01 on August 24, 2007, 06:06:19 pm
So the red and yellow wires tapped on the CPU pins are the ones connected directly to the RCA jacks, right? But I'm not sure; is that yellow wire split in two and tapped on the top and bottom part of one of the CPU pins or is it just some extra piece of plastic he didn't take off? And the mono audio is located where on the board? Sorry for being such a noob :-\
Title: Re: NES stereo output mod
Post by: 133MHz on August 24, 2007, 06:26:18 pm
No problems man ;). But looking at the dude's wiring confuses me a lot while the schematic is really easy to understand. About what you're asking: apparently it's a piece of stray insulation (the one that touches the bottom part of the resistor). Either that or the shielded wire is grounded to that point As I suggested earlier, don't look at the pictures, it will confuse you (and me) a lot more.

EDIT:Also, is it good to get a dual potentiometer? The guy doesn't mention that.
Title: Re: NES stereo output mod
Post by: keiffer01 on August 24, 2007, 06:33:38 pm
ok i'll try not to look at the pictures. ;D But when I check the schematics I don't have a clue on what to do. Since you know what to do, could it be possible to explain me clearly step by step? :) I opened up my console and I'm looking at the board right know, and I'm trying to figure out to where and to what to connect the mono out. :)
Title: Re: NES stereo output mod
Post by: 133MHz on August 24, 2007, 06:36:39 pm
Mono out:
(http://www.raphnet.net/electronique/nes_mod/images/mono.jpeg)

Channel 1 & Channel 2:
CPU Pin 1 and Pin 2

I can make a crappy-mspaint drawing if you want ;)
Maybe get a good hi-res pic of a NES motherboard and draw on top of it

My sister took the digital camera with her until tomorrow so I won't be able to snap any pictures for today :-\
Title: Re: NES stereo output mod
Post by: keiffer01 on August 24, 2007, 06:45:57 pm
Yeah that's it! I'll take pics of my NES board, send them to you, and you can like paint the wires showing which goes where! I'll take pics right now. ;D
Title: Re: NES stereo output mod
Post by: 133MHz on August 24, 2007, 07:02:01 pm
Crappy Mspaint-drawing at your service! ;D
Title: Re: NES stereo output mod
Post by: kite200 on August 24, 2007, 10:35:23 pm
actually that's really good and easy to understand, can we get that stickied on the site in some misc section
Title: Re: NES stereo output mod
Post by: keiffer01 on August 25, 2007, 09:45:02 am
Yeah now it's easy to understand! ;D But I'm missing a few parts to start on the project...electronics store here I come! ;D
Title: Re: NES stereo output mod
Post by: 133MHz on August 28, 2007, 06:52:33 pm
EDIT: I made nice little text links to the files, but my crappy hosting doesn't allow MP3 hotlinking (though they allow it for images), so I had to remove them and break the links to avoid you from reaching their stupid 'Don't leech us' page >:(. So you have to copy the URL and paste it into your browser and remove the exclamation sign in http to hear them. Sorry.

Hi everybody!

I've been wondering how this mod would turn out. Electrically I think it will sound great, but really didn't want to punch more holes and solder more wires to my beloved NES without knowing how it would turn out. So I made some mock-ups with the computer (using Winamp w/NSF plugin and GoldWave) to approximate how this mod would sound like ;D.

I worked in WAV and converted the final products to MP3 (you know, the heaviest WAV is about 15 MB, overkill for the ones with teh slow internets) and found MP3 really destroys NES music >:(, but anyways here they are:

Headphones recommended!

Here's the worldwide known Super Mario Bros. Overworld Theme ;)
MP3 files, 96Kbps 44kHz CBR, 1 MB each:

* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme Joint Mono.mp3
SMB Theme in all its mono sound glory

The NES sound processor (built in on the CPU die) generates two square wave channels, a triangle wave channel, a white noise channel and a DPCM channel (for digital sound, not used in SMB). You can think of the square wave channels as two guitars, the triangle wave as an electric bass, the noise channel as a drum set and the DPCM as the vocals of the NES ;). The Famicom has an External Input on its cartridge connector so games with their own sound hardware (built onto the cartridge itself) could add extra sound channels by mixing them with the Famicom audio.

Both square waves come through Pin 1 of the CPU, triangle, noise and DPCM come out through Pin 2. They get mixed by some resistors and directed to the Audio out of your NES.

* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme squares.mp3
Here's how taking audio just from Pin 1 would sound like

Only the two square waves.

* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme triangle&noise.mp3
And here's Pin 2 output

Triangle and noise channels.

* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme Basic Stereo.mp3
'Basic' Stereo NES output mod

This is the common stereo mod, it just takes Pin 1 audio and routes it to the Left channel of your TV or stereo system, and Pin 2 audio to the Right channel. If you listen to it, it will sound stereo, but sounds a little 'dry' or 'weird' to me, like forced, and actually it makes me a little dizzy listening to it with headphones :D.

The Stereo NES output mod discussed here mixes back the mono sound onto the stereo channels by a variable amount (set by how much you turn the variable resistor's knob, so the square wave channels get a little from the triangle and noise, and viceversa), giving more 'life' to the sound, it sounds more like a real stereo song to me.

I simulated the stereo mod with the knob set at 20%, 40%, 60% and 80% of its travel:

* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme Stereo 20.mp3
NES Stereo mod, 20% mix
* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme Stereo 40.mp3
NES Stereo mod, 40% mix
* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme Stereo 60.mp3
NES Stereo mod, 60% mix
* h!ttp://usuarios.lycos.es/dogbert/stereones/SMB Theme Stereo 80.mp3
NES Stereo mod, 80% mix
(play with the balance on your volume control to note the subtle differences)

At 0% there will be no mix and it will sound like the basic mod (full stereo separation), and at 100% there will be full mixing, producing mono sound again (no stereo separation).

You can think of it like having a band, at 100% separation the two guitarists at the extreme left side; the drummer, bassist and vocals at the extreme right side. 
At 0% separation everyone in the center (mono)
and at some intermediate value just like a real band stage placement (a little mixed).

So the dual pot controls the stereo separation of the channels to suit your tastes and particular songs. These sound better uncompressed BTW.

And a bonus track ;D!
* h!ttp://usuarios.lycos.es/dogbert/stereones/chipndale_stereo.mp3
Some Chip 'n Dale song at 50% separation

Actually this is the first attempt I made, it's a little sloppy with the timing and such, but sounds pretty acceptable for me.

Any comments, suggestions, etc. I will be very glad to hear them :D.
Title: Re: NES stereo output mod
Post by: UglyJoe on August 29, 2007, 06:14:41 am
I'm pretty sure Notso Fatso (http://slickproductions.org/notsofatso.php) will let you mix the NSFs directly in winamp.  That way you won't have to deal with Goldwave.

Also, the DPCM channel is used more for drum samples than vocals, I think.  Usually one of your square channels would be the "vocals" of the song.
Title: Re: NES stereo output mod
Post by: 133MHz on August 29, 2007, 09:01:40 am
Yup, but when reading or hearing DPCM the things that come to my mind are those horrible digitized voices that some NES games have ;D