urrth is an Amp Simulation. Use your own effects in front for a solid-state clean jazz vibe or throw in a distortion pedal to bring out the true character. The amp is naturally bassy and the M (middle) dial seems to give the most audible affect on the sound when cutting/boosting.

There is a bit of compression built in so that when pushing the amp too hard it will squash the sound rather than give you those ice-pick highs. There is no cabinet simulation so you will need to use your own (IR) loader.