The Red channel on the 5150 III 100 watter is dry sounding and tight, just not AS dry and tight as a VHT. The EVH is more forgiving, but still very heavy.
I still think the 5150 III is one of the most brutal amp with a 7 or 8 string guitar. This amp, channel 3, gain anywhere above 12:00 and master volume anywhere above 11:00 is insane. Of course, coupled with the 5150 III 4x12 cab.
When I played the III, I thought it had more in common with an Uber (but tighter and not as messy) and some Soldano flavor. Also could pass it off as a much meaner XTC.
I think it's very different than Engl or Diezel but it's a GREAT tone and can be very pummeling for the metalz.