Something not to miss in this history: Boss GT-5
Pretty much *the* role model for any floorboard modeler. I should one day get mine out for a photo session, but I actually don't exactly know in which of the countless old stuff boxes in the basement it lives. Still absolutely intact.
Used it for the first gigs where DI/silent was a must (theatre stuff), in favour of the POD, which I also bought later on (I think the GT was released 2-3 years earlier, too lazy too look it all up), simply because the GT was much more dynamic and flexible. I only later learned that it's got an analog drive section, quite amazing.
I also used it along with a Marshall 6100 - gotta say that even these days that'd be a pretty potent rig (had some noise issues with 4CM at first but got them solved using one of the cables without ground connection).
I should actually really take the thing out and see whether it would still prodce some decent sounds with an up to date cab sim.
Had a built in PSU, which was great. Individual switches for each FX block was also really nice, that way you could easily modify patches. Just scrolling through everything with the arrow keys was pretty tiresome, there's been no multiple encoders for individual parameters.
Fwiw, the thing does both gapless switching and delay/verb spillover.
Apart from a signal flow display and more encoders, this is still pretty much exactly how each and every floor modeler works.
Here's a picture (unfortunately not mine, but I will take one, should I find it - mine looks a lot more rock'n'roll):
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