This is going back about 9 or 10 years, but I've built a couple JTM45 variants and a couple 18 watt variants. Second amp I ever built was an 18 watt 1x12 combo faithful to the original circuit. Next amp after that was an 18 watt head with treble-middle-bass control. I hung on to this one for a bit and had it alongside at least one of the JTM45s. I had ample opportunity to swap both through the same 2x12 cabinet that I also built. Both were wonderful amps capable of warm, bright cleans, sweet overdrive and killer rock crunch. In terms of volume, the 18 watt TMB and the JTM45 were pretty comparable, which was surprising 'cause my original 18-watt 1x12 combo wasn't terribly loud (but very very sweet and the most mesmerizing tremolo I've ever heard). The tone *was* a bit different. The 18 watt had a nice thick and creamy midrange quality - like a vox-esque Plexi - and the JTM45 was warmer sounding, a little less gainy with more more bottom, less mids, and more highs. Slightly more Fender-y cleans. I miss both amps dearly!