Home Features Boss Announces the GT-1B Bass Effects Processor, RV-500 Reverb, MD-500 Modulation, and the Katana-Mini Guitar Amplifier Boss Announces the GT-1B Bass Effects Processor, RV-500 Reverb, MD-500 Modulation, and the Katana-Mini Guitar Amplifier planetsixstring June 23, 2017 comments off Tweet on Twitter Share on Facebook Google+ Pinterest The GT-1B features 90 unique effects including 13 different preamp types.