To my knowledge, the Original and Rev 2 are identical except for the Rev 2 having a gain potentiometer with a more gradual taper. I suspect the differences in tightness would be affected more by speaker/cabinet/tube/guitar/pickup/tuning/pick choices than the gain taper. The signal paths are electrically identical and the gain range is the same, just with a different curve from min to max. If there is a perceived difference in tightness, it is likely to be from the variables listed above or from the inherent variation from amp to amp in a manufacturing setting. I know there are tonal differences between the Uber revisions, but i would bet any revision can be made to sound "better" (more preferable to the beholder) than another with a personalized set of peripherals (aka guitar, pickups, cabinet, tubes, etc.).
If the tube bias won't go low enough for the current tube set, you will need tubes in a different range. I went through this last time I retubed mine. the tubes i ordered wouldnt go into range, so the tube supplier let me return them. they then sent me a set that was in range. However, if i recall correctly, 32 mA is pretty close to where you want to be anyway.
-russell
