AMP (Amplified Music Products) was founded in Chatsworth, California in 1981 by Russ Allee and Roger Smith. This is verified, according to California records, that AMP was registered as a corporation in 1981 in California listing Russell V Allee as president. Before AMP, Allee earned his reputation when he worked for the Acoustic amplifier company and designed the 360 and 370 Series of bass amplifiers. After forming AMP, he had another former Acoustic employee named Steve Rabe design the preamp for the new AMP Model 420 bass heads.
Rabe left AMP to found his own company called SWR, which stood for Steve W. Rabe, where he developed his own preamp. Allee continued on with AMP until the company folded in 1988. Gibson reportedly bought AMP after they closed and began offering their "new" GB 440 bass amp that was nearly identical to the AMP Model 420. While unverified, Allee either designed Gibson's GB 440 Bass or Gibson simply used Allee's Model 420 and called it the GB 440. Allee also worked with David Nordschow of Eden Electronics to develop Eden's World Tour Series of bass amps. Regardless, AMP's Model 420, SWR's SM-400, Eden's WT-800, and Gibson's GB 440 are all very similar in design and appearance, but users all agree that each amp sounds different and has varying amounts of pros and cons.
The author would like to thank Neil Springer for his AMP contributions.
Amplifiers and speaker cabinets previously produced in Chatsworth, CA between circa 1981 and 1988.