Guys, the OP is asking about the Lone Star
Special vs the MkV35, so the power tube stipulation isn't relevant. He asks a fair question because they both use EL84s.
Mesa's statement about the V35's Clean and Fat modes being based on the Lone Star is obviously authoritative

but in practice it always seems like there's still some difference with other amps about which this is also true, or so I've long heard (I've never compared them myself). Having hung around here as long as I have now, it usually comes down to the Lone Stars having a little extra magic of their own that people miss once they "upgrade" to one of the Marks or an Express or whichever.
Personally, I think the LSS is an absolutely amazing midsize combo that handles pedals really well and has a clean that can only be beat by its big brother the LSC, and even then it's mostly just a question of trading off muscle for finesse.
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LP Std Gold Top | LP Special | AmDlx Strat | AmStd Tele | SG Std 60s | ES335 | FSR Tele
Lone Star Classic
Lone Star Special
Electra Dyne
Mini Rec 25
TransAtlantic 15
Lone Star 27, 23 & 19, RA 27 1x12, WBCB 1x12 Cabs http://www.damonwood.com