Krell Power Consumption

" what the supposed effect of PFC is on your amp or sound?"

If done right - enourmous !!!

It suppose to make your power supplies fully regulated i.e. to remove ripple and other terrible artifacts power supply do create - usually resulting in addional ear-piercing odd-order distortions.

I don;t know if Jeff Rowland audiophile or Spectron Audio pro audio amplifiers power supplies with PFC are fully regulated.....

Dan D'Augostino (spl?) is expelled from Krell and part quality go down and so the sound...

Mark Levinson was sold to Harmon Group... The same group which in 1970's bought famed names like Infinity and converted it into mass production junk.

The co-founder of Infinity, John Ulrick started then "Spectron Audio" and went to development of new class D amplifier mostly for pro-audio (and introduced first hi-fidelity one in..1974).

I always was "toobeman" and never tolerated Krell/Mark Levinson for brutish sound but now with my B&W 802 Diamond I needed very power amp and I drive them by Spectron monoblocks. Paired with flagship Joule-Electra full tube preamp its the best system I owned or auditioned.

You are talking about cost of electricity, heat (and weight) and.... cannot get out of "brand names" class A behemoths !!!!.

Did any of you tried high quality class D amps like Spectron, Jeff Rowland(312), Weiss etc [ I do not mean cheap junky class D with noisy switching power supplies ] ?

However, if you still insist on class A begemoths then there is new generation of such amplifiers, much more musical and involvong then Krell/ML. These are BAT600SE, Plinius Reference & Pass Lab XA200.5 - none better then my Spectrons but classical class "A"....

Magfan,

I believe Jeff Rowland did fine job with ASP modules but his main achievment was development of very high quality of switching power supplies with Power factor Correction, PFC - making this power supplies highly regulated. It was done in his "312" amp. Interestingly, Spectron uses switching power supplies with PFC in their pro audio amps but in their hi-fi amp, Musiican III they use traditional transformer based power supplies

The rest just (IMO) grabbed ASP, placed into their chassis, put their label (the best added their midor mods) and sold.

Bel Canto Ref 100 MkII has added battery of electrolitic capacitors improving power supply.
H2O uses (like Spectron) traditional power supply with B&O which improve sound.

However, my post was specific for this thread dedicated to the titans of 1980's - Krell and Mark Levinson - now 30 years later new geberation of class A and class D (and others) amplifier are available. not cheaper, as a rule, but...better in sound.

"I'd be curious to know how PF and regulation relate. "

Hello Magfan: It is that PF correction, as I wrote above, remove ripples and other "terrible" artifacts which produce odd-order ear-piearcing harmonic distortions. Please see below from Jeff Rowland web site:

"External JRDG PC1 is active Power Factor Correction (PFC) units. These devices preconvert the AC from the mains to a steady 384V DC current fed into the monos through a banck of intermediate charge capacitors and make the "501" much less sensitive to AC noise and fluctuations. They also keep the 501s internal caps optimilly charged avoiding AC induced ripples. PC1s should yield even larger authority to the "501"s and will give them a lot more subtlety and nuance"

mote "avoiding AC induced ripples ".

Effects of ripples and other things on distortions are desribed in Simon Thacher of Spectron paper:
http://www.enjoythemusic.com/magazine/manufacture/0708/index.html

All The Best