The first ABM models produced in 1998 featured "Klystron Bass Magnifier" across the front control panel, and the original output was at 200W. After a few hundered were produced, they removed the Kylstron trademark at the request of another manufacturer who had already registered it and began producing amps with "Ashdown Bass Magnifier" across the front. The output power was also increased to 300W around this time.
Originally, these models all had pale blue control panels along with black speakers. In 2002, the speakers were changed to the Ashdown Blueline speakers that appear blue through the grille, and the whole series was designated with an EVO behind the model number (i.e. ABM-C110-300 EVO). In 2005, the third series of the EVO models was issued called the EVO II Series. Noticeable changes include combining the inputs into one with an active/passive input switch. The power sections were also upgraded. In 2008, the fourth version of the ABM was introduced as the EVO III that features a new built-in compressor with compression level knob and switch.