Hi Guys I have a stock standard Orange AD200b-factory tubes. I am finding it lacking particularly as I push the gain past 12(o'clock)- It thins out and loses bottom and definition. Am considering swapping the power section to kt88's plus is it worth changing to lower gain preamp valves (at7's/ au7's?) Are there any Mods commonly done to this amp? About the only thing I have really read about is changing the Iron to a Mercury Magnetics transformer (for mixed review of improvement). I am happy with the amount of power it has Just wanting to keep it balls and bottom heavy throughout its range more. Any help,experience or suggestions appreciated. C.