I used and was happy with the onboard compressors on my various SWR (and a GK) amps for over 20 years. I never turned them off. But when I switched to a smaller rig - my SWR SM900/Goliath III 4-10 cab is wonderful, but with the work I get these days it's like driving an Formula One car to the convenience store - I found how much I depended on those onboard compressor/limiters for my sound. That down-sized rig I bought is a Fender Rumble 500 (2-10s). Loved the sound (and the weight), but didn't notice until I'd handed over the money that it didn't have a compressor. I tried using my old red MXR DynaComp guitar compressor, and quickly learned it wasn't designed to deal with the low end of an E-A-D-G four-string guitar bass (at least not my old fretless Stingray and mid-'70s P-bass). So, a friend gave me one of his retired studio workhorses, a dbx 163X Over Easy Compressor/Limiter half-width rackmount. Not sure that it's the answer, though it's certainly better than nothing. Maybe I just haven't worked with it enough, yet, but it has only a single slider control and a trim (input sensitivity) pot. No ATTACK or other compressor parameters. Then again, the SWR and GK amps didn't have more controls on their compressors either. Not sure if I'd get something more out of using a dedicated bass compressor pedal with all the extra variable parameters most of them have. Looking for some advice on the dbx rack unit vs. what a pedal could do for me, if anyone has experience with both. Besides cost, my considerations are that I've already got that dbx unit, it uses 120-volt AC "wall" current and saves on 9-volt batteries and the floor clutter of a pedal, but on the other hand, the dbx needs either a rack or some kind of a mount which doesn't fit into or onto the Fender Rumble 500. On a related subject, Fender really pissed me off by buying a great bass audio company, SWR, then killing it and not supporting its loyal customers. And, secondly, Fender, besides putting a compressor in the Rumble 500, you could make that amp's knobs stay in place better? A weak breeze is almost enough to change my settings. I put rubber bands under the knobs to provide a bit of friction and better hold them in place. Cheesy looking and feeling workaround! I'd prefer Fender had designed the amp with detents on the controls, or even just friction discs to hold the knobs in place. On the other hand, the Rumble 500 sounds great, only weighs 38 pounds and was a bargain compared to anything else I found with a sound and weight I liked.