Just a quick demonstration in the difference of expansion audio via an ENIO exp board using CVIII (Akumajou Densetsu)as an example.
For more information on the ENIO board (device that enables expansion audio that I plugged into the bottom of my system):
So a few things here. The quick answer: Yes. All you do is plug it into the expansion slot on the bottom of the NES. Long answer: You will need a famicom to NES adapter to play Akumajou Densetsu on an American NES that is also soldered to support expansion audio. That can be found here:
https://store.retrofixes.com/products...
The route I used however is an Everdrive N8 flash cart with proper mapper support to output expansion audio. Either way will work, it's just user preference. The custom expansion audio mappers can be found here late in this thread (links on first page are expired but were reuploaded):
https://krikzz.com/forum/index.php?to...
As to where to buy this device, it can be purchased here:
http://nintendorepairhut.com/accessor...