These amps came both with and without. Is the compressor decent on these, or is an outboard compressor the only way to go? Never had an amp with a built in compressor that was any good until the Fender 800 Pro which is excellent. Curious about these.
I've never tried an ABM, but if it's anything like the Rootmaster then it is one of the better on board compressors out there. My favorites are actually the TCE SpectraComp and the Ashdown. They also have an auto gain built in so that as you increase the compression the volume also increases. Really cool. While other amps compression just sound like squashing limiters, the Ashdown Rootmaster actually thickens up the note and makes the Drive sound tighter. Again I am talking Rootmaster here, but I would imagine that the ABM would be similar if not the same or better. Hope this helps.