I tried this tube in my Behringer V999 first, as a replacement for the rather wild Bugera-tube it came vith. It gave a minor/slight reduced drive and added some clarity to the sound. Not even close the 60 % reduction I might expected. (By the way, this was not the place I bought it for.)
It was purchased to be placed in V1 or V4/PI-pos in my VHT special 44 (or a V1 or V3 (PI) slot in my Hotrod DL), and I tried it first in my VHT V1 pos. Same result; just a slight reduction in gain/breakup. No big deal.
When this was placed in the V4/PI-slot it really showed it's worth: the quality of the sound improved on almost every aspect! Depth, clarity and general sound experience went to a new level (...of confidence and power..! Hi-hi)
I've ordered one more for my Hotrod DL, this is a killer in PI-pos!