Super NES Digital Audio Mod

I've posted a handful of threads over at the gamesx mod forum about this mod but I wanted to get more opinions on how best to accomplish this project as well as the potential pitfalls. This mod is definitely going to require some finesse as it calls for soldering onto a surface-mount IC that has extremely small traces to work with. Actual engineers have told me that this is going to be problematic and could potentially ruin my console because when you subject any IC -especially such a small one- to extreme heat and electrostatic energy, you are prone to electronic failures that manifest themselves in many ways. I just would like to know how best to approach this project in a way that's going to keep me from ruining my SNES while tapping the best possible audio signal from this machine. Thanks for your time!

 

The hard part is finding a SNES that has the appropriate board inside as well as the fact the clock isn't 100% compatible with what is needed.

 

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That's what I'm saying! Some guys over at the gamesx forum have done this mod and said that it's absolutely well worth it. The 60 Hz hum and other noise issues are completely eliminated and the signal-to-noise ratio is drastically improved. I am looking for more people that have done this so I can get some good advice.

 

Every SNES I've ever opened has had a different board configuration than the one he used for the mod, this is the sole thing that has stopped me from attempting this mod.

That and my only coax input based speaker system died a few months ago.

 

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But you need a soundcard then that can sync to 32khz (and can record at that rate)... my M-audio "Fast Track Ultra" can't record 32khz but can sync properly so you can at least listen to the noise free sounds
To record 32khz do i have an older PCI soundcard "Delta Audiophile 24/96".

 

Have you tried capturing from the Microsoft Sound Mapper/MME-WDM/Wave Mapper (it may be called any one of these things in your audio app)? If your out-of-spec audio is playing fine in the background that should work.

 

I can only record the s/pdif input by choosing "windows directsound" and record 8 channels and the 2 last is the s/pdif, so i need to delete the other 6 channels when the recording is done and make the 2 remaining a stereo track. This does not work for 32khz even if i hear the sound perfect... it just gives a distorted sound when trying to record it.

 

That sounds like a really cool idea.

On a related matter, there's something I've been wondering about for a while. Is there any difference between coax-based and optical (toslink) based S/PDIF? They both carry the same signal, right? Is there any reason to use one over the other?

 

What are you using to record?

 

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In that example so did i mean "Fast Track Ultra".

Druid II: this is how FTU sound when i try and record when i have the S/PDIF (32khz signal) connected.. http://www.ym2149.com/ftu_spdif_32khz.flac

the audiophile 24/96 can record at several rates like 8khz, 9,600khz, 24khz, 32khz etc... but not at the sample rate it is synced to thru S/PDIF, only the preset rates, it does not sound as bad as the FTU, only playing at faster or slower speed depending on what rate you select to record at... example recording a 44.1khz sound at 32khz will make it sound slow and recording it at 48khz will make it sound too fast.

BTW: i am "Stefan_L" at the gamesx forum that zedrein linked to in the first post, i have done several S/PDIF mods on arcade games (and SNES)

 

I meant what software package? Anyway, change it up and see if you get any further. If you're hearing it, Windows is coping with it, and that means one way or another you can record it.

 

SPDIF hardware needs to be able to capture at any arbitrary rate, it does this by greatly oversampling the signal. If the control software outputs a 44.1kHz file just change the rate in the file header to whatever it truly is. Since the data comes out of a buffer it should still be lossless.

 

Yes i have done some tests of that earlier.
Here is an example recording from Taito F3 arcade PCB (Top Ranking Stars) that was recorded at 44.1khz and later i changed the sample rate of the recording to 29.762khz.
http://www.ym2149.com/spdif/top_ranking_stars_spdif_ingame.flac

 

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The only difference is in the physical transmission, they are the exact same signal. Personally I think optical is stupid and a waste of money. Coax can easily handle data rates in the MEGABITS lol. If SPDIF supported 7.1 24-bit PCM @ 192 kHz coax could handle it without much worry as it's ~10% of the cable's bandwidth.

 

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But you can damage optical cables by bending them too far or stepping on them and they are unitaskers. More equipment will only have coax input/output so that's a good reason to use it too. I think Toslink was just a novelty of 1999.