the vipre and the 1073
are really two different animals...
the GT is a pretty darn good high end TUBE pre. clean and very big sounding.. The draw back is that it has a sad history of breaking down.
if you can get one at a great price and have schems to fix if needed.. try it...
is a classic.. even the reissues sound great.. its more of a MID forward thrusting sound pre.. (if that makes sense)
i agree with the others.. if you can post samples of both youll get a much better response..
Best of Luck!