I just picked up a 1979 Princeton Reverb (Pull boost is foot switchable). 1. Should the voulme taper on this thing? Mine went from off to loud pretty quick and starts breaking up around 3-4. I took out the crappy pre-amp tubes and there was an unlabled tube in the 12AT7 spot. I replaced that with a Mullard 12AT7 and replaced the 12ax7 and 7025 with Mullards as well. The amp sounds A LOT better with NOS tubes but still breaks up pretty early. The power tubes are new JJs. 2. Would swapping a 12AU7 in spot one, or other lesser gain tube tame it a bit or is there something wrong. The amp sounds pretty good to me and the reverb and tremolo both sound strong and good (as strong as a trem on a PR can be).