the next time you buy equipment (particurlarly an amp) from a dealer (which may be a while given the deals floating around here), open up the box, take out your new gear, plug it in and compare it right then and there to the dealer's demo. sometimes the differneces are subtle, other times they are not. it's hard to suggest what to listen for, as different components burn in differently. it's probably a safe bet to suggest that you listen for a less harsh, more fluid sound. do it right then and there (warm your new peice up if you think it necessary). otherwise, that spectre of acclimation may well affect your judgment. cheers.
