NES Stereo Modifications with Easy Schematics


The NES came with a standard mono output. This was perfectly acceptable in 1986 but with the advancement in home theater systems and Chiptune musicians stereo separation is needed. This modification will bypass the hum inducing RF box, greatly improving the sound quality.


Two different Stereo methods are listed  
 1. Mono Mixing:  Mono mixing blends the new stereo channels with the original mono line. Interesting old school Mod. Note: This mono mixing article is old and "archived" I do not recommend this old mod for most DIYers.

2. Direct Stereo Output: will not require pots or knobs. RCA jacks connect directly to the sound chip. Cheaper and easier. Super Simple and my preferred method.Classic mod and works great!


Mono Mixing Method:
Supply List: 
10k-50k Volume Pots (I used a 24k) Note: You can also use dual gang pots (2 in 1 body)
Knobs x2 (optional)
RCA Mount Jacks x2
1uf Capacitor x2
Insulated 26awg Wire 1-2 feet

Start by removing the NES motherboard. If you need help view my other article on a full breakdown.


Locate Chip RP2A07A, prepare your wires and solder directly to the chip pins or at the beginning of the neighboring resistors R4 & R3, whichever is easier for you. 


Next up is drilling holes and sorting out the location of your knobs and RCA jacks. I picked the back of the NES but others prefer the top case, front etc. The schematic and sample photo should explain everything regardless of RCA and Pot placement. Post a comment or contact me directly if you need help.



Location of Ground and Mono Channel

Direct Stereo Method:
Supply List: 
RCA Mount Jacks x2
1uf Capacitor x2
Insulated 26awg Wire 1-2 feet


Direct Stereo Output
For this method follow the schematic above. No pots or knobs needed, much simpler process.



If you have any questions regarding this tutorial, please comment below




14 comments:

  1. This has helped me so much! Thanks for the clear instructions!!

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  2. Confused. Wouldn't the mono go to pin 1 and seperated audio to the wiper?

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    Replies
    1. I don not understand your question.

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  3. Hello. I have a doubt: would removing the RF out improve the sound or video quality at all? Doing just that, I mean.

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    Replies
    1. Since the RF modulator in the Frontloading NES is also designed to output Composite - removing the unit would require you to build a video amplifying circuit. You'd need to buy a 2SA933 transistor, a coupole 220uf 6.3v capacitors, and a 100 ohm, and 300 ohm resistor... I think.

      Then you would have to know how to assemble that onto a PCB, and connect that to your NES. You would also need a separate Audio Amplifier in order to get any sort of sound out of the console.

      To answer your question. No it would not improve video quality. In fact - you'd lose the ability to even output video from the console.

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    2. Checking out the Nintoaster build on youtube, you can apparently get away without the RF. A video amp is needed, but can be fashioned with a simple 2N4401, a 220 ohm and a 33 ohm resistor. Audio can apparently be run without amplification, but it'll come out quieter. That's up to you.

      From test footage, it doesn't seem to affect it either way. If your RF modulator was screwed up like mine where it would warp the image, it probably would fix that.

      Sauce:
      https://youtu.be/YDGR2MiCyYs

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  4. I done the simpler method of the mod. I have pc speakers hooked up and it simply seperates the waves instead of blending them. Before I had a y splitter running both of the same signals out of the one audio out port on NES which sounded good this just basically splits it not sure yet which I like best both sound pretty good.

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  5. On the direct stereo method, are the capacitors used to amplify the sound?

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    Replies
    1. No but they do help protect the CPU with possible voltage spikes from the RCA jacks.

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    2. Is there anything that can amplify the sound or is just turning up the tv a little more the only option? And thank you for the response.

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  6. Hi I had a question about the 4th picture. Do you solder the red wires that intersect the 1st pin of the 24K pots?

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  7. Hi, I can't find the right potentiometer. Where might I fine one?

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  8. I'm having an issue when hooking it up to a dual pot, the stereo sounds like normal but the mono gets like if its on a lose connection, I've changed wires and resoldered everything like 10 times now. I've tried hooking up the wires to legs and to the holes. Any idea what I am doing wrong?

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Have Questions? Comments?