Last night, I was playing the Ketron SD4(sound module not the arranger module) and I was kind of surprised that it sounded bad through my headphone! I've always liked Ketron sounds. Then I played some VST instruments through the same headphone. Very rich and full sounds. I think my ears are spoiled by some quality VST sounds.

Anyway, I can't play the SD4 from vArrnager through the SD4 USB port. The SD4 will freeze up. It is a known bug that Ketron has not fixed. I was going to buy the Ketron SD1000, but I found out that it can not be powered by the USB port. A faulty part in it. No more Ketron for me unless Ketron changes their business practice. From what I hear the SD40 still seems to have issues. I decided to give up on the SD40.