I can somewhat gauge an amp's output from a look at its circuitry. It's reassuring to at least see a few name brand parts in there. Say I crack open my darkvoice, and see all the 3rd-world looking parts in there, makes me a little nervous that they're going to die an early death (although a blurb in the manual claims these parts outperform foreign parts). That, and I'm just curious how it is designed. The Arietta does use op-amps, but so does the entire Meier product line, as well as all the designs from Headroom up to the $4000+ max series.
The 336SE, now that I've suffered with this CMOY all of Christmas break, is pretty kickass. Sure, I had to repair its power switch when it came broken (it's flimsy as a popsicle stick) by simply hard wiring it to be always-on and it's full of shady Chinese parts, but it's still built with love and sounds cool. Sure, it hums with all the tubes besides stock tubes (3 new-production preamp tubes hum, and counting), which is why I spent more than 1/3 its value on tubes coming in the mail from ebay to try to fix the problem. Tubes and HD650 are meant to go together, everyone says it, because of the high current demands of the HD650. It's not even a matter of pairing "bright" with "dark" components and so on...solid state works fine for K701s but there aren't too many affordable solid state amps that are a good match for the HD650 according to my research.
I'd like to know if Skylab has tried the Arietta with high impedance cans like the HD650 and had good results.
Yes, the stock tubes are weak. You'll probably still like how it sounds...the Sovtek preamp tube I bought sounded worse than stock. The electro-harmonix sounded pretty boss, even with hum. The tung-sol sounded in-between, with plentiful hum. Skylab says the hum can be fixed with the addition of a few parts and a fair bit of soldering, but I'm not cool enough to attempt that mod. Instead I'm going to keep trying tubes, because the stock tube doesn't hum, and it's possible that the NOS tubes from the 60s that I ordered, according to a recommendation, will not hum as well.