^^^ That's the best approach. Also, I don't know what compressor you were using, but it probably wasn't a good one.

Leave it off. Set the combo amp's EQ flat, set the Sadowsky's EQ flat. Also, and seriously I mean no offense by this, but be sure to read the manual for the amp to be sure you have the right knob settings for "flat". Sometimes flat = all knobs fully counterclockwise. Sometimes flat = all knobs at noon. Sometimes flat = "2,10,2" (Fender-style tone stack, with knobs numbered 0 to 10; lows at 2, mids at 10/maximum, highs at 2). And there are many more ways too! On my fave preamp, flat = 8,10,2... go figure! Point is, make absolutely sure you know for a FACT what the flat setting is.
AFTER getting a good basic sound with the EQ flat, just make small adjustments from there--it should not take much EQ to get a decent tone.
Another thing, the combo's 210 speaker box may just not be able to handle the bassy tone you might like. Try getting ahold of a larger speaker cab, and see if using that doesn't solve your problems.
