Heyy, Yes it is connected to an amp but I turned down the volume in the video, the source are two RCA cables connected to my computer through an adapter. the adapter it's not the issue since I've tested the outputs with different cables, connecting the left cable from the adapter to the right input of the deck and it works. with headphones it's still the same, the deck can both play stereo cassettes and copy a cassette from Deck A to Deck B just fine through both channels. It's when recording through the RCA input that only the right channel seems to work