I play in a cover band, and have to switch tones and effects often several times within a song, as well as between songs. I've been using Boss GT effects for several years (now a Boss GT-10) through a Mesa Roadster amp. I use the effects on the GT-10, but the tone is purely from the amplifier (why use digital models when I have a Boogie). I play in small clubs and have rather limited space for my floor effects, which included the GT-10, the Roadster footswitch, and a crybaby wah (the crybaby has crapped out, so I'm using the wah on the GT-10).
I wanted to be able to switch amplifier and effects patches simultaneously using the MIDI output of my multi-effects unit. The Mesa footswitch takes up a lot of space, and switching sounds often requires changing both the multi-effects patch and the amp channel (two-step!). The Roadster footswitch also has a mute button inconveniently placed and easy to hit. I wanted to bypass the footswitch and only have the multi-effects in front of me. Not being a very techy player, I really didn't know where to start.
After a bit of research, I went with the Amp Gizmo (RJM Music Technology), mostly because it was well-rated in the very few reviews and discussions I found for this kind of technology. There is a rather expensive and proprietary cable to connect the Gizmo to your amp of choice (the cable is specific to your type of amp, but RJM supports a wide range of amplifiers), but it will actually control any amplifier parameter you normally control with an amp footswitch. It was really easy to set up, and all I had to do was program the channel, boost, and effects settings for each patch on the GT-10. The GT-10 sends a MIDI signal to the Amp Gizmo, which then changes the amplifier channel (and/or lead boost, reverb, etc.). Oddly, switching is now smoother than with the Mesa/Boogie footswitch; I don't get a surge, or lag, between channels anymore.
The down side is that I lose the degree of freedom of being able to switch amp channels within the same GT-10 patch. Each patch on the GT-10 has to be programmed specifically with the channel on the amplifier, so you have to plan out in advance how the banks are used in each song. I've gone from using six banks (four patches each) of effects for our usual 60-song set to 19 banks. The wiring array is pretty messy, as I use a four-cable method, plus the MIDI cable; I keep them bound with velcro straps and the tips color coded to make the system idiot-resistant.
In general, I'm quite pleased with my rig these days, but I am curious to know if anyone else out there has messed around with this kind of tech (either the Amp Gizmo or any other kind of MIDI switching/interface) and what your experience has been. What other switching technologies are out there?