In the studio, Morello uses the same setup for the bulk of the guitar tracks. For "The Battle of Los Angeles", he also used a few other amplifiers, such as a Line 6 as heard on the clean, spacey intro of "Mic Check", plus a Pignose mini-amplifier and a MusicMan "Twin" style amplifier. During the recording of Audioslave's last album, "Revelations", Morello experimented with different amplifier setups. For the title track's solo he split his signal to his standard Marshall 2205 head and Peavey cabinet and a 100 watt Fender Bassman head and an Orange cabinet. With delay sent to one while the other is unaffected the sound is being "ping-ponged" between the two amplifiers. He also borrowed a Vox AC30 amplifier from producer Brendan O'Brien for some tracks.