Tried the hairdryer it did not seem to alter the slight hiss. The funny thing is this guitar is silent in my Tmax, my Trace AH 250 and in the swr combo I have. Its only in the mark bass head and combo where it makes a slight hiss.
WHICH leads me to:
I borrowed and older 4 string jazz bass passive reissue with genuine single coils. That hummed slightly if you only had one pickup on when I tried it in my tmax, my TE and my swr combo
BUT when I put it through the markbass cmd102p it was silent with only one pickup on.
Im now more confused than when I started
skez