Having settled n with my NHB-18NS with new batteries, I've learned to use the BTM feature whereby the preamp uses AC while keeping the batteries on full charge like a laptop. While not as good as battery operation, this mode is okay when not listening closely, as when reading, etc. The advantage is that the batteries are always charged up for serious listening. So I have a question. Operating on AC, would the 18NS benefit from the use of an aftermarket power cord? I suspect it would but would appreciate your input.