What does a Hexfred do?

BTW: There are manufacturers that appreciate the diffs that better rectifiers provide. ie: Note the upgrades that are available from Rogue(http://www.rogueaudio.com/The_Magnum_Series.htm)

and Cary Audio(http://www.caryaudio.com/upgrades-and-modifications/)

Hexfred? Poor Fred, he didn't understand why the bad witch cast that awful spell on him.

Is this why my ARC CL-60 always had a nasty "buzzsaw" ghost riding the waveform of vocals? It has tube output stage but solid-state rectifier.

It was either this, a Classe DAC (solid-state) or digital jitter (maybe all three?)
that just drove me up the wall.

I hear it from time-to-time with my current system but to a much lesser degree.

Can't the demons just leave me alone???

Rectifier conducts until amplitude of AC voltage is lower
than capacitor voltage (just after peak of the sinewave). At
this point diode is reverse polarized and diode current drops
to zero. Unfortunately it will conduct for a moment in
opposite direction and then it will recover back to zero.
Ideal diode should be very fast to minimize current spike in
opposite direction and very slow to recover to zero. Ratio
of time (on negative side) after the peak to time before the
peak is called "Softness Factor" (RRSF - Reverse
Recovery Softness Factor). You want fast diode to minimize
negative current spike, but not the one that snaps back fast
(you don't want narrow spikes).