"Whoa.... rock n' roll."
—Marty McFly

The amplifier with Marty standing in front, ready to rock.

A CRM-114 amplifier was present in Dr. Emmett Brown's garage in 1985, and measured about 8' x 8'.



Marty receives a telephone call at Doc's garage from Doc himself.

Marty had asked Doc to help build him a "mega-powered amplifier and speaker" on October 12, 1984.[1]

When Marty McFly entered the garage to play his guitar, he turned up the amplifier's volume and overdrive knobs all the way. Playing a single "power chord", he was suddenly thrown backwards into a bookcase, and blew the speaker out. Seconds later, the telephone rang: it was Doc, who had called his own home, warning Marty — too late — that it might overload.

Some time after returning to 1985, Marty repaired and upgraded the blown-out speaker to be more accommodating and resilient to his high-decibel requirements. By May 1986, it was up for sale. Marty used the amplifier to trick Biff Tannen, sending him across the room, and allowing Marty to take Doc's notebook from him. Fortunately, no visible damage was done to the amplifier.[2]

Behind the scenes[]

  • The CRM-114 is the nomenclature of the Strategic Air Command encryption/decryption device aboard the B-52 Stratofortress in the 1964 film Dr. Strangelove.
  • Screenplay writer Bob Gale confirmed that Michael J. Fox performed his own stunt when he was thrown backward, presumably suspended on hidden wires.[citation needed]
  • This scene may be a reference to music videos in which loud guitars throw someone backwards, such as the 1984 music video for "We're Not Gonna Take It" by Twisted Sister.