Name Mesa/Boogie began with a practical joke when Smith was commissioned to secretly convert the 20-watt
Fender Princeton of a local guitarist into a significantly louder 100-watt amp without altering its appearance. He accomplished this by replacing the amplifier section with that of a
Fender Bassman and replacing the 10-inch speaker with a 12-inch speaker. To ensure the joke would work, Smith asked
Carlos Santana, a customer at Prune Music, to demo the amp. Despite initial skepticism at the sight of the seemingly stock amplifier, Santana played it and was impressed, exclaiming, "Man, that amp really boogies!" Released in 1972, the Boogies solved the issue of amps not having enough gain to sustain notes at volumes suitable for smaller venues. Smith produced a number of custom variations of the Boogie through the late 1970s, with options including reverb, a five-band graphic EQ, various speakers (most often
Altec or
Electro-Voice),
koa wood jointed cabinets, and wicker grills. The IIC was introduced in 1983 to fix a noticeable "pop" when switching channels, while subsequent improvements to the effects loop resulted in a handwritten "+" designation on the rear of each amplifier's chassis. Notably, this new IIC+ variant also featured an altered preamp to create a more aggressive sound, with a strong midrange focus and tight low end. Combined with its graphic EQ, the amp excelled at "soaring lead sounds and huge crunch chords."
Guitar World cited the IIC+'s use on
Master of Puppets as the primary reason for its "holy grail" status in the rock and metal genres, while noting the amp was also a favorite of top session musicians at the time like
Steve Lukather. As the Mark III was already deep in development, fewer than 3,000 IIC+ amps were made during its short production run between January 1984 and March 1985. Additionally, some players had earlier Mark II models modified to IIC+ specs. The IIC+ is Mesa/Boogie's most valuable amp on the secondary market, with models often selling for over $15,000, as of 2023. and sporting a characteristic steel, diamond faceplate, the Rectifier was Mesa's take on a "big, monster-metal head" and intended to look threatening compared to the Mark amps. with then-75-year-old Smith joining Gibson as "Master Designer and Pioneer of Mesa/Boogie and beyond." In this capacity, Smith oversaw the development and release of the Mark VII amplifiers. In mid-2024, Gibson announced that Smith was no longer with the company, having "completed his time" in his prior role. ==Notable users==