Ok a little background first, I have been playing guitar for a long time and as such I have owned quite a few tube amps. One of these amps happened to be a Mesa Dual Rectifier. Now on the back of Mesa amps you have a switch to go from tube rectifiers to SS based rectifiers. Now if you are into guitar then you will know that the only advantage to having tube rectifiers is power sag. Which some like, but most don't so most every modern tube amp uses SS rectifiers. Also to note why this is, it is the sheer fact the RECTIFIERS HAVE NO EFFECT ON THE SIGNAL CHAIN"S SOUND.
There I said it so again why are Head-Fi folks changing or "upgrading" thier rectifiers. Actually having amp sag in a audio amp is a bad thing. Believe me what I say as I made a name for myself as a local amp tech where guys were bringing me all there amps for bias adjustments, cap replacements and so on. If I had a Woo say I would replace the rectifier with
this even though it might no look as "pretty" which it seems some are more concerned with looks rather than sound
. What you don't want in a audio amp is when your source puts out it sudden peaks for your power section to sag.
Again any amp tech worth his salt will tell you that the rectifier has zero effect on the signal chain. Now you can change drive tubes (your biggest effect) or your power tubes to change a amp's sound signature. So one last time, "Why are Head-Fiers worried about their damn rectifiers?"