It's possible that in my situation, it's an amp/pickup combo. I only have one bass preamp. It's a very good one, but when tweaking the knobs, the midranges aren't very prominent. Something that I'm reading about when researching on the net, and experiencing on hand concerning an Alembic F-1X.

The pickups in the RBX170 bass seem to be filling that void. It is possible that in another setup it would be considered too mid heavy. I'm not experiencing any muddiness or distortion out of them (which is pleasing) and the mids are cutting through clean. The Ultra Jazz pickups seem to lack mids, and in this amp, I don't think that's a good thing. It could very well be that Ultra Jazz pickups are perfectly fine with other amps. Same thing, no mud, but they're lacking in power and mids, and it doesn't agree with this amp.

For THIS amp, the stock Yamaha sound much better. I think that before I try buying new pickups for the Samick, I'm gonna put in the stocks with new pots and cap and see if I get the same results as the Yamaha.

Anyone else here experience any similar experiences with " lower end" gear before?

That makes sense. Do they make a mid boost for bass? I guess a EQ before the F-1X would do it.