Was thinking about it today. I have an Orange TT... I think it has plenty of gain, but just realized today that only one of the "pre's" is actually a pre-amp tube. T'other is the PI. So I guess I understand, now, why the OR15 is thought to have more gain than the TT... it's got 3 "pre's", so one assumes one of those is the PI and t'other two are actually used for gain. I mean, it's a single channel amp, so one assumes both pre's are used for the single channel, not split to cover more than one channel. Forgive the wandering... PI in every tube amp?