Personally when I think of an amp with mojo, that means an old amp with a saggy tube rectifier, or a single ended amp with negligible sag, and a vintage speaker that distorts a fair amount when then amp is turned up. Preferably the amp should have between one and three knobs total and 50's cosmetics with frayed covering at the edges and a leather handle that is falling or fallen apart. You need an amp that is displaying entropy in order to get the implication of infinity and natural decay into the guitar sound.
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I don't think you get it from fabulously expensive new amps, boutique or otherwise. Maybe dollars are inversely proportional to mojo. You might have it within yourself and your music and channel it through such an amp, but those amps themselves leave me cold compared to the old stuff.
Whereas, everybody that plugs into my old Watkins Dominator or Selmer Zodiac or Noble Super or Grampian Vibromajor or Stentor Super 12 or Vox 710 or AC15 or Gibson GA-8 (parallel single ended dual 6V6 version), has wide eyes, and shuts up and plays for a while, differently than they normally play. Then they talk about the experience the next several times I see them.
I'm not saying everybody should feel this way. YMMV and it's no problem for either of us if it does. My main point is that depending on what it is that you like about old amps, new reproduction or tribute versions may in fact be completely missing the point.