He uses hot-rodded Marshall JMP Superbass II amplifiers from the late 1960s/early 1970s. Each amp, with a nominal output of 100 watts, is used with a 4x12 speaker cab and a custom-made 4x15 cab. He uses two such stacks, one on each side of the drum riser. For many years the amps were nicknamed "No Remorse", "Killer" (left side amp) or "Murder One" (right side amp) with appropriate nameplates. "No Remorse" was subsequently replaced by a new amp nicknamed "Marsha" when, as Kilmister said in an October 2004 interview, it "blew up". "Killer" and "Murder One" were believed to have been destroyed in Argentina when all the other equipment was stolen but this was later proven to be untrue. In 2006 Marshall designed new, prototype versions of "Murder One" which were then put into production, and the original amplifier was retired. A limited number of these bass heads have been released by Marshall in 2008 as the "1992LEM", a signature series copy of Lemmy's 1992 100 Watt Super Bass Head, "Murder One".
The phrase "everything louder than everyone else" sums up Lemmy's sonic approach, as he plays at the loudest possible levels. He uses the bridge pickup exclusively (giving his bass sound more definition) and turns all the tone and volume knobs on the bass up full. On the amplifiers, he turns off the bass and treble and he turns the midrange up all the way, with the volume and presence up to the "3:00" position. The result is a biting, mid-range, almost guitar-like tone which is somewhat distorted but not "fuzzed out" or "blurry", a formula well-suited to his use of open-string drones and power chords. Lemmy uses no effects pedals: the distortion is produced naturally by the amplifiers, as they are set at such a high volume.