I used a PP-2 for awhile and I upgraded the power supply to something around 500mA if I remember correctly. The sound was a little more open. The difference was easily heard and definitely for the better. The PP-2 definitely sounded "closed in" and a little "gritty" with the stock power supply, which I do feel probably provided insufficient power... or maybe there was a lot of voltage drop during peaks due to the non-regulated power supply being loaded to near it's full capacity...
I eventually got rid of the PP-2, mainly because I felt the bass didn't have much weight. It was fairly "round" sounding with the upgraded power supply though... not too bad... It has a built-in subsonic filter that can't be turned off. I suspect that could be what I didn't like about it.
I found a power supply on eBay cheap (for a printer). I spliced and soldered the plug from the old power supply onto the new one. Ugly... but it worked. Whether or not I'd pay a lot for a wall wart with the right plug or save up for a better phono stage instead... I don't know... You're probably going to want to be able to tweak loading and capacitance before long. A phono stage with those capabilities can make all the difference.
