Tube Watts vs. Solid State Watts - Any credence?

@Bombaywalla ... "I'm not even treading into the realm of "is 14dB too much global negative feedback?"!! ;-)" Scardy-cat! :) LOL

Re NFB: FWIW, many years ago, I recall speaking with either Lenard or Kal (ARC customer service tech rep; Len has since retired) ... I can't remember which one now ... and I asked about ARC's use of NFB in their amps. The answer was that many electrical variables are taken into consideration when designing an amp. So ... ARC's end product is the result of many engineering compromises that are made to achieve an optimal result. No perfect answers or solutions to an engineering problem that entails making trade-offs.

@Bombaywalla ... do you understand the term "[o]utput stage coupling is a combination of “ultralinear” and Audio Research’s patented “partially cathode-coupled” topology ..."?? I have a rough understanding of ultralinear .... No clue about "partially cathode-coupled” topology. Any idea??

Tried it again and the 8ohm taps definitely sound better all day long compared to the 4ohm taps. Who knows?

10-10-15: Ebm
Bomb you may suck wind DUDE!!

Dude, *dont* get personal here w/ the name calling. No one's doing it to you so you better return the favour. I wont say it again....

10-10-15: Djfst
Tried it again and the 8ohm taps definitely sound better all day long compared to the 4ohm taps. Who knows?

there's a good explanation for it as stated in my earlier post. I guess you missed reading it??

Bifwynne,
yeah LOL! ;-)

@Bombaywalla ... do you understand the term "[o]utput stage coupling is a combination of “ultralinear” and Audio Research’s patented “partially cathode-coupled” topology ..."?? I have a rough understanding of ultralinear .... No clue about "partially cathode-coupled” topology. Any idea??
Bifwynne

well, this is a serious case of the blind leading the lame but I'll give it a shot. I hope that somebody who knows more steps in....
'ultra-linear' is a global negative feedback technique where, in a tetrode (4 active electrodes) or a pentode (5 active electrodes), some part of the output (usually present on the anode or plate) is fed back to one of the screen grids of the tube. The amount of output signal fedback depends on the tube type (KT88, 6550, 6V6, etc). David Hafler has patent on this where he fed back 43% of the # of primary xformer turns to the screen grid to linearize his amplifier. What this global negative feedback did was reduce output distortion, reduce output impedance & raise the output power to near-pentode levels.

'cathode-coupled' is a tube amplifier topology where the input tube is cathode coupled to the next gain stage tube. here are some pix for you to look at (you can drag your mouse over the pix without any harm. Click on the pix at your own risk!)
http://www.bing.com/images/search?q=cathode+coupled+amplifier&qpvt=cathode+coupled+amplifier&qpvt=cathode+coupled+amplifier&FORM=IGRE
the 1st pix itself should be good enough to allow you to visualize what I wrote.
In the pix the 2 tubes are strongly coupled as there is a deliberate connection between the 2 cathodes. The issue with this amp is that the cathode of the input tube is at a very different voltage than the cathode of the 2nd tube. So, this amplifier becomes very sensitive to power supply variations & noise. Thus, I'm *assuming* (you know this goes!! ;-) )that ARC has a patented technology where they partially couple the 2nd tube to the 1st tube so that they can make the cathodes of both tubes operate at nearly the same voltage while still transferring the input signal to the 2nd tube to amplify it.
I could be out on a limb here.....