Sorry, I really should have thrown links around then.
Step 1 is most real world suppliers are awful (I barely trust Frys or Radio Shack to sell me batteries) which means online or bust. Ebay and amazon are nice for some things (I have not checked here) but I would be half surprised if something suitable for this existed here.
This means big boy electronics suppliers, warning right now they tend to come with a hefty shipping bill unless you are buying above a certain price (if you ever see kits for this sort of thing on ebay then chances are some got a load from a proper site and bundled it), are part of a school or a big business (if you know someone with electronics hookups then have a chat).
Those that still work in the US (most of mine are UK or Europe based) are
http://www.newark.com/
http://www2.mouser.com/
http://www.digikey.com/
I was mainly looking at digikey for this.
http://www.digikey.com/product-sear...-ics/linear-audio-processing/2556582?k=cs8406 is the audio chip. You have a choice of a few different packages, the guides use SOIC and that is what I specced for the board below but TSSOP is an option. I have not looked properly to see if there would be a more suitable chip for the purpose here (
http://www.digikey.com/product-sear...=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=25 if you wanted to start having a look).
http://www.digikey.com/product-detail/en/SN74LVC2GU04DBVR/296-13276-1-ND/484500 for the inverter, I misread as well and had the bulk price rather than the individual (cut tape or tube if in doubt). It will then be 60 cents.
Seriously though it is basic components to make one (even radioshack/frys will have this in sufficient quality) more than fast enough (most of those have switching times in nanoseconds, audio is in the low kilohertz and I doubt the emphasis switches on or off even close to that often, if even more than once a game)
http://www.allaboutcircuits.com/vol_4/chpt_3/2.html has more on that.
I have not looked to see if I can source one of those adapter plates.
http://www.digikey.com/product-sear...t=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25 has something but it is quite pricey and the most suitable one was not in stock.
I watched the video.... I think we witnessed the start of the loudness wars as they apply to games there (though commendably they did not amplify to the point of clipping or even interpolation clipping) so I could not see much in it.
However if they left off the emphasis stuff, and it does look to be an oversight on their part, then it might be an issue for part of it. Not enough for me to call potentially a night and day difference but enough to make me pause.
Again though if you just want something you can more easily feed into an amp or something then it does not matter.