The best separates between $2500-3000. Moving on from the original Rogue Sphinx Intg..

Al. Thank you for the response. The link you sent clearly show the back of Sphinx original integrated. I received an e-mail back from a Rogue tech named, Nick, who basically  reproduced the bullet points I sent you. He indicated that  the variable input ( pre-out) was used to connect a second amp or subwoofer. 

I emailed back to clarify and confirm whether that connection will "bypass" the Sphinx internal amp, and most importantly ,also allow the pre-amp controls to function with the outboarded amp in place.

Maybe, I am just dense, but I need to confirm the use of the all the pre-amp functions  when used with the outboarded amp.

BTW,  the Ayre V5xe is too expensive for me at $2900. I have not inquired if the seller would accept a lower offer, though only 6 days remain on his ad. But, I appreciate the heads up.

The information that the ARC 100.2 not being a variation of class D amp design is good news. That may account for the rave reviews it received in  a few mags, and customer testimonials. Though, you point about its an age and possible diminished sound quality is a viable concern

Lastly, there was a review in Tone magazine of Van Alstine's FET Value CF Vacuum Tube Pre-amp Line stage ($1899)  by one of its staff writers. The review praised it build quality and its overall sound quality, but there was some hesitation on the writer to crown it the best pre-amp in the under $2000 range. He did highly praise the built in phono as a steal at $249 ( as noted, there is a MM/MC stage for $329, both are optional). 

Jeff Dorgay offerd some follow up comments and felt some of the criticisms of the pre-amp's restricted soundstage was system or amp related  His experience with the unit was a big soundstage with either AVA own amp, or PASS Labs, ARC, Simaudio, etc. 

Thanks again to all who have offered comments. 

He indicated that the variable input ( pre-out) was used to connect a second amp or subwoofer.

Schubert 4-10-2013:
I bought myself a new AVA Synergy 450 for XMAS, it much outclassed the Odyssey amp I was using, very dynamic and enables me to hear every line in the Symphonic music I primarily listen to. My biggest complaint is cheap plastic speaker terminals placed in tight space pretty much limits you to banana plugs....

Schubert 12-31-2014:
I have had a Synergy 450 for 2 years, first time in 40 years I haven't been looking for a different amp.  Sounds like a high-quality 100 watt tube amp using NOS output tubes better than any currently available.  Easily betters the Hafler, Odyssey, Belles, McCormack and Quad amps I used before.

Does the NuPrime ST-10 digital amp (150 RMS) qualify as a Class D amp, or a variant of Class D?? 

NuPrime bought out the former NuForce company, and redesigned the entire line of components.  Some units have received  good  to VG reviews, the ST-10 amp in particular.  However, it is  a new company who knows where it will in 5 years.   Thanks, Jim 

Does the NuPrime ST-10 digital amp (150 RMS) qualify as a Class D amp, or a variant of Class D??

Although the ST-10 is a “digital” power amplifier, it is not a standard Class D switching amplifier. According to NuPrime’s owner’s manual, “Instead of the conventional sawtooth configuration, NuPrime’s patented circuit design uses an analog-modulating signal that adds neither noise nor jitter. Rather than reverting to off-the-shelf solutions, NuPrime’s in-house advances have further unlocked the switching amp’s potential without the difficulties pure digital-switching amplifiers simply cannot avoid.” The cliché that should follow would be, of course, “Not your father’s Class D amplifier.”

The term "class D" is sometimes misunderstood as meaning a "digital" amplifier. While some class-D amps may indeed be controlled by digital circuits or include digital signal processing devices, the power stage deals with voltage and current as a function of non-quantized time. The smallest amount of noise, timing uncertainty, voltage ripple or any other non-ideality immediately results in an irreversible change of the output signal. The same errors in a digital system will only lead to incorrect results when they become so large that a signal representing a digit is distorted beyond recognition. Up to that point, non-idealities have no impact on the transmitted signal. Generally, digital signals are quantized in both amplitude and wavelength, while analog signals are quantized in one (e.g. PWM) or (usually) neither quantity.