Open Hidden Sound Channels in the NES

Hidden Sounds?

The original Famicom (Japanese Nintendo) consoles are superior in design compared to the American NES. One long forgotten feature is the extra sound channel, this extra channel was disconnected on US console and removed from US games. Castlevania 3 is a classic example. The original Japanese version has a much different theme song.




With the development in modern SD card to NES adapters like PowerPak/EverDrive kits and Famicom game adapters it is possible to play Japaneses games on the NES & hear the lost sound channels.



Original Famicom
 Note: This guide is for the classic American Nintendo NES-001 front loader. This will not work with the later redesigned top loader NES-101. 

Disclaimer:  This mod requires basic soldering skills and understanding of electronics. Please do not perform this mod without the required skills.  I will not be held responsible if you damage your NES. Follow these instructions at your own risk

 

Supply List:


To get expansion audio activated you only need to add a resistor inside your NES.

  • Phillips Screwdriver Medium Sized
  • Experimentation suggest using a resistor ranging from 24k up to 56k.  Pick a range in the middle and test the sound. The sounds with PowerPaks, Everdrives vs Real Famicom carts can vary.
  • Soldering Iron & Solder

If you need help dismantling a NES please view my tear-down article. Here.
The Mod area is located under the black cartridge loading  tray.


Solder a resistor between pins 3 and 9 of the NES expansion connector.  The resistor value can be changed to get different volume on that channel.  This area is located on the top of the motherboard, near the infamous 72 pin connector.







So there you have it, super simple mod and fun.  

If you have any questions let me know!


33 comments:

  1. Would 20ohm make the extra channel louder and 50ohm make it lower in volume?
    which end of the ohm range do you think is better?

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  2. Lower ohm = louder volume.
    Hope that helps. Thanks for stopping by!

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  3. So what is the result? Does adding the channel back actually affect any US games? Do the US games have an extra sound channel in their BGM that doesn't play until the hardware support is restored by this mod?

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    Replies
    1. Only works with Jap games or Everdrive

      "With the development in modern SD card to NES adapters like PowerPak/EverDrive kits and Famicom game adapters it is possible to play Japaneses games on the NES & hear the lost sound channels."

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  4. Hi I was wondering about when you said that this mod is compatible with the stereo mod, does this mean that even when the sound channels are activated they only work when the NES is in stereo? Or will this mod work without the stereo mod?

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  5. Hi, I did this mod along with the stereo mod. I can hear slight bleedthrough of the VRC6 channels through my stereo output, but I can't hear the VRC6 output at all. (It does work via RF and Composite though so the mod did work). Because I'm using this as a recording thing, do you think it might be beneficial to just wire Pin 9 to its own audio jack? (I used 1/4" jacks instead of RCAs) .. I'll likely try it but wanted to get your insight. Thanks :)

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    Replies
    1. Yes this mod only works with the original Mono output. If doing stereo mods and this mod changes need to be made. Someday I will update this article. Basically you need to find the source for the expansion audio and solder that to one of the RCA jacks. The CPU pins do not output expansion sound.

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    2. Retro Fixes, MOSSJ32 has a point; you're acting unprofessionally by having thin skin over vulgar language. (Not everyone will agree with you about wanting to avoid profanity.) To make this worse, you pulled the "throwing tantrums" card, which isn't what professionals do.

      Delete
    3. MOSSJ32 has been erased from history. You never read the original post. I stand by my throwing tantrums remark because that is exactly what he was doing.

      Perhaps if he was called out more often he would learn some life lessons.

      Simply put, I do not tolerate vulgar language here. It's my site and my choice. I want visitors to have a positive experience here and some of them are minors.

      If you prefer vulgar language & "brat attacks" start a website and express yourself. I will not stop you.

      Delete
  6. I rigged up an NES deck so I could swap in various resistor levels and found that 24k was WAY too loud. Testing with Castlevania 3 on the EverDrive N8, the expansion audio was overpowering the internal audio channels at 24k. So I gradually stepped up in resistor level and found that 56k was the sweet spot as far as the EverDrive pipe-in goes. 47k was a hair too loud.

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    Replies
    1. Thanks for the feedback. Was your Everdrive setup for HI or LO expansion audio?

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  7. In your Youtube video demonstrating the expansion audio, you used a red pushbutton to toggle it on and off. How did you get that wired up in conjunction with this mod? Thanks!!

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    Replies
    1. Simply have the switch wired to pin 3 and 9 (plus resistor) ON/OFF toggle will enable and disable the circuit.

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  8. I did this, now my nes is making a buzzing sound from hell, even after i removed the mod again :(

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    Replies
    1. Double check your work. Make sure all the pins are clean around 3 and 9. Remove any solder or flux and clean with rubbing alcohol.

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    2. Gonna try to clean it, i also tapped the audio straight from the cpu, no buzzing sounds there so thats a good start

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    3. A good cleaning sorted it out, thanks!

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  9. Would this mod work with a PAL NES? (japanese games can be played on a PAL NES but will be slower, would be interesting to hear the additional channels even if it's slower though)

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  10. hi, I been reading up on this post, I was wondering what is the wattage of the 47k ohm resistor, I also read somewhere else, if your using real Famicom carts, 94k ohm resistor might be better, any thoughts on this? thanks!

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  11. Hi, can I use this 100k trimpot multi turn instead of resistor?
    http://www.mantech.co.za/ProductInfo.aspx?Item=35M0848
    Thanks in advance

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  12. Does anyone know what resistor I should get for playing Famicom Disk System games using an NES to Famicom adapter?

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  13. I'm using the FDSStick, not the actual drive, if it makes a difference.

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  14. Also, can electrical tape be used instead of soldering?

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    Replies
    1. Heeeeeell no, Sorry I don't intend to be rude but no, no, no.
      If you can't solder = Do not mod.

      You will have a very unreliable connection and risk shorting the system.

      If you are using FDSStick disk via NES to Famicom converter it will not work. The existing adapter boards on the market do not allow expansion sound.

      In the near future I will offer my own brand on game adapters. These will have audio enabled for special applications such as yours.

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    2. Could you answer my question, please?

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    3. Link was dead. I don't know. Just find a few cheap resistors. Give em a try.

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  15. Mine isn't a brand name adapter, it's one from an NES Excitebike cart. Does the same situation apply?

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  16. ok that would be a Famicom to NES converter. Same applies for that adapter. It needs to be modified for extra sound channels (plus the console). I have a few modded adapters in my store. I don't have guides for adapter mods (at this time)

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    Replies
    1. So if I buy your modded adapter, and then follow the steps in this article, will I have the expanded audio?

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  17. My adapters allow expansion audio from Famicom Games. It should work with your Disc Emulator but I personally have not tested that device.

    Though I don't understand how you are using Famicom Ram adapter with frontloader nes?

    Sounds like a hot mess.

    You are welcome to purchase an adapter. I have no idea if it will work with your setup.

    Or I can try modding your current adapter. Though I am a busy guy and free time is limited.

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  18. If you take your toaster NES apart, you can fit the Ram adapter in the cartridge slot. But with a modded console (the region locking removed), a modded adapter (from your store), and following the steps here, it should work (forgetting about the FDSStick, and pretending I'm using an actual FDS), right?

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  19. could i use a 100k potentiometer instead of resistor?

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  20. "could i use a 100k potentiometer instead of resistor?"
    of course, I'd guess it would be best to get an "audio taper" one but any should work.

    ReplyDelete

Have Questions? Comments?