Some of the greatest sonic benefits in this hobby are achieved via power supply mods. ie: (http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1238465914&read&keyw&zzmullard+5ar4) That refers to the improvements in a power amp, in which the output stage's gain is realized as current(read the post following his rectifier replacement). Your pre's gain stages are all voltage, but the voltage that's modulated(YES- that IS the correct word) by the signal, and conveyed to the next stage, all comes from the wall outlet, via the power supply. The tubes you choose to use in your PS can have a dramatic effect on your presentation.
