John Frusciante’s Mesa Boogie Head (Unknown)

John used this amp in early 1991, although there are very few photos or videos of him actually using it as the band played only five gigs in early 1991, before taking a break to work on BSSM album.

Based on a statement that John gave in an interview dated February 1991, at that point the amp was halfway broken, and John was already thinking about a replacement.

As far as amps go I have a Mesa/Boogie, and I don’t know what kind it is. But it’s two amps in one. The knobs are frozen in a good spot. I can control the volume, just not the treble or bass, but I don’t have a problem yet. I’m sure it’s going to grow little legs and walk away from me soon.

Guitar (UK), February 1991

Note – based on John’s description, one would assume that he’s talking about a Mesa Boogie Dual Rectifier, however, photos seem to show something different. Below is a capture from a concert played on January 24, 1991, in Los Angeles. We see John playing through two amps, a Marshall on the left, and what appears to be a Mesa Boogie (not 100% sure) on the right. Unfortunately, the exact model is a mystery. If you happen to know what it is, be sure to leave a comment below.

One possibility is that it could be a Musicman, as pointed out in the comments by Thwacko. But, the metal label on the top left seems too wide compared to the one fitted on Musicmans.

By October 1991, and the start of the BSSM tour, the Mesa Boogie was gone, and John started using two Marshall JCM800 heads instead. Interestingly, John already used the same exact model year before in 1990, before switching to Mesa Boogie, so it’s unknown what prompted him to make a switch in the first place.

I like to keep things simple. Those MESA/Boogie amps were too hard for me to understand. For most of the basics, I used two Marshalls: a guitar head for edge and a bass head for punch and low end.

Guitar Player (USA), October 1991