I have a nes powerpack with the loopy mappers, which I downloaded from here https://www.dropbox.com/s/2vbdj43u2kvu15b/ULTIMATE MAPPERS.rar?dl=0 I also modded my nes to play expansion audio . Games like the Japanese Castlevania 3, play with correct mmc 5 audio. I got recently an adapter from tototek to use the powerpack on my famicom. The adapter I bought is this one . The powerpack plays perfectly, but due to the nature of the adapter, expansion audio isn't reproduced . I did a little research and found that I need to do some minimal mods on the adapter, as described on this guide on krikkz forum https://krikzz.com/forum/index.php?topic=5189.0 I followed the guide and music on Japanese Castlevania 3 plays correctly, but sound effects are muted. FDS games with expansion audio, either have music or sound effects only. Any idea why this happens? I read some guy's youtube comment, that he replaced one resistor with a 10k ohm potentiometer, since the powerpack has a low audio volume. I haven't tried it yet, but I'm going to do so.