Panama showcases Eddie Van Halen's legendary brown sound in its most refined form. The Frankenstrat with a single bridge humbucker runs through a modified Marshall Super Lead with an MXR Phase 90 adding subtle modulation. The tone is thick, warm, and harmonically rich with that signature compressed sustain. The Phase 90 adds a gentle swirl that thickens the tone without being obviously phasey.
Both run real Marshall circuits in 20-watt format, but a JTM45 with KT66s and a 1959 Plexi with EL34s are different amps. Here's which Studio you should buy.
Both are 20-watt small-format Marshalls with the original Marshall circuits inside, but a 1959 Plexi and an 800 are different amps. Here's which Studio you actually want.
Marshall's Studio Vintage line has three 20-watt heads (JCM800, Plexi, and Silver Jubilee). Here is which one fits which player, and the settings that prove it.