I've got a stereo RCA-mono 6.25mm convertor to output from my SP-404 to my PA.

However, I've encountered an odd problem - it's not outputting properly this way. Some samples (mostly drums, I think) are ridiculously quiet, while others are normal volume. Perhaps the quiet samples are mono? I'm not sure.

Shouldn't an adapter like the one described above just combine the stereo RCA channels into a single one, maintaining volume/etc?

If I'm missing something obvious, please let me know.

maybe its something to do with the cable's rudimentary way of combining left & right, and the phase differences between left & right as opposed to mono L & R being identical.. could cause cancelling issues i guess. . .I dont know alot about that kind of stuff though so I could be wrong.