I believe Boulder uses complimentary BJT (bi-polar) output transistors in their amps, these are far better for current delivery into low impedance, and better suited to low impedance and -phase angle EPDR load of the Sabrina than complimentary Mosfets (Pass) would be, I don’t know what the other amps use.
From 50hz to 200hz they have an nasty loading for amps to see, especially at 75hz.
I can’t speak to the Sim Audio or Goldmund but I had the Pass and Boulder at the same time and tested both with Wilson Audio Sasha 2’s. The Pass is a really terrific amplifier but to my ears on the Sashas, the Boulder was clearly superior. The dac and streamer is surprisingly good. The dac section gives up nothing to the Aqua La Scala Mkii Optologic from one of my other systems. As an aside, I also chose to purchase the Boulder and previously passed on a Gryphon Diablo 300. As a matter of fact, this is my second Boulder 866 purchase. I dont know how they did it for less than $20,000. Go hear one to see what you think. It may or may not impress you equally but its astonishing what Boulder has achieved with this one.
The all new Wilson Sabrina X is coming out next month !
With the same DNA as Wilson’s very high priced Flagship speakers !
Check out the AVM Ovation A 8.3 integrated. It has enough power to drive the Wilsons, has a wonderful feature set and a neutral to slightly warm sound profile that will compliment them beautifully.
Full disclosure, I am an AVM dealer but that is more because I am a huge fan of the product line than anything else.
I auditioned the Dag Progression integrated with Sabrina X's this weekend.
It was being used only as a power amp, with a DCS Bartok as the DAC/streamer.
It sounded fantastic, really brought the speakers to life over the McIntosh gear to my ears. Though I can't vouch for the fully integrated Dac on the Dag, nor am I fan of the looks (a little blingy/espresso machine for me), I'm positive it's a great pairing for the original Sabrinas.
I'd like to try them with the Moon gear as well, as they pushed some of the other reference speakers I tried really well.
sonictomb, I own the Wilson, D'Agostino, and dCS combination. I use Transparent Audio cabling with this combo. Each these four companies use the other's products (but different components of each company's products like the Alexx V, Vivaldi, Momentum) are used in voicing their own component. That is why this combination sounds so great together. I had the Sabrina and dCS Bartok and was hoping my Pass INT-150 amp would not be bettered by the Progression amp, but it wasn't close (multiple friends all agreed it wasn't a close call). The only problem is that you can't unhear how good they sound together, so you better be ready to pay the price, or just don't hear them all in your home on loan from a dealer that carries all these brands!