fitting massoth sound card to usa trains gp9 in analogue

[knobby]

trying to fit eMOTION XLS f7 us diesel 8220057 sound card to usa trains gp9 for analogue mode.a bit of fabrication required for hardware,not a huge problem.followed wiring instructions as far as i can see,trouble is that the sound is just like static instead of a diesel sound.has anyone experienced this before and can help please?