Got my XPA gen 3! Heres what I think.

[leonski]

Lonnie:
The person who shifted frequency used what is basically an amplifier / oscillator at 120hz. So, 60 comes in, 120 goes OUT. Of course, this SEVERELY limits output power based on amp heat sinking and such.
For some reason I think it was a PSAudio Perfect Wave product from QUITE a while ago.
The top line product in that line will output 1500 watts with NO mention made of powerfactor AND runs 5 large.

PFC being a rectifier and switcher? On an industrial scale, I've heard of large inductor or capacitor banks.

[Lonnie]

Interesting, will look into these.

Thanks,

Lonnie

[leonski]

I just got a note back from Paul M. over at PSAudio. Seems I remembered right.


From Paul:

Yes, we did for many years. The P600, P300, P500 were all with variable frequency adjustments.



Available on the used market they are No longer in current production.

[jeffreybehr]

FWIW, I ordered on 13 Jan. an XPAGen3-2.5, that is, with two mono and five stereo modules. This will biamplify my Revel C208 CC speaker and all eight (or, eventually, 10) surround and ceiling speakers*. But first, I'll connect it to my main speakers, Vienna Acoustic Mahlers which I've improved a bit with better tweeter caps and biwire capability.



I've been considering hi-end poweramps for a couple months for the Mahlers and their replacements this summer, a pair of Revel Salon2s, and finally settled on a pair of PS Audio BHK 250s to biamp pairs of either-model speakers. I didn't think of this at the time, but having this amp will also allow me to judge the sound quality of this new Gen-3 amplification. I'd love to be able to buy, with good audiofile-conscience, a pair of XPAGen3-2s or -3s for LOTS less money than a pair of BHK 250s.

We'll hear what we hear!


* and will allow me to retire and sell two Butler TDB 5150s and a humble Outlaw 7100

[leonski]

Check out the Magtech if you get the itch. A very powerful and stable power amp. One version features a regulated PS while the other version with the same output section features a different PS which is claimed suitable for Electrostats.

And I can't imagine a Hi-End amp search which would be complete without mention of Pass Labs.    The XA30.5 which is no longer in production was 30 watts in 'A' per channel with  about 6db of headroom over THAT in A/B at that point.  
Before I realized the expense was way more than I could afford, I considered a pair of 'em for my Panels with an ALLXO.   MiniDSP was the logical choice for crossover.   

And speaking of crossovers, you could replace the crossover in your Mahlers, go active and really make the most of biamping.   Because of the variable gain of the Mini, you don't need to worry about amp gain which was at one time the bug-a-boo
of biamping.