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Woof. Whilst cynics should go loopy over non-standard reviews covering prototypes, enthusiasts appreciate it as the only correct response to a unique opportunity. Going in the precise path forward wasn't mapped. I'd simply catch the balls Nelson would throw. Since I've penned formal reviews for them, I'd use his own F5 and J2 as comparators both for his sake and that of our readers.

Because the formal nomenclature of Nelson's first SIT amp was unknown until production committed, I ran through the preview phase with an entirely unauthorized NewWatt working title. It indicated that we're dealing with a newly minted output device. Nobody has ever heard it before. It's history in the making.

June 19, 2011: Time flies. "The amp is still imminent. At the moment I have locked down a version which sounds consistently good but which is not likely to be the final product. Now that I've succeeded in making more than one of them sound alike (no easy feat) I'll make a few more. This will happen when I get back from Sea Ranch next week. Keep in mind that what I'll be sending out is only going to be a teaser of some sort. I'm still sorting out issues and probably the final product will use a different circuit and "sit" in some other chassis design. - np"

July 19, 2011: "As usual, my apologies for being not communicative. I have an amplifier prototype for you going on the burn-in rack when I get back to Foresthill. I figure to give it a week and then ship it out. This is but a prototype piece but I think it will give you a good taste of where the final product will land. Better probably not to tell you anything about it in advance. It will be more interesting to compare notes after you've had time to play with it. By the way there is no hurry as the only other piece will be going to Jon ver Halen. You can photograph the interior and feel free to comment as you like. This will be the stereo unit and there will be a mono unit as well. Both are scheduled for shipment in October. - np"

August 1, 2011: "Shipping the amplifier tomorrow. Sherilyn will shepherd it out the door to the address you gave me. Then I'll head out to the coast where I'll be until the 19th or so escaping the heat to write and do artwork. Jon will just have to wait till I get back for his -:)
Nelson's coastal think tank

"This is simply a prototype. I expect production to be slightly better and certainly neater inside. The input impedance is plenty high but it does appreciate an ordinarily low source impedance. Passive preamps are probably not the best approach. I don't think you'll be able to break it so don't worry about that. After you take a listen, drop me a line and I'll fill in the specs. On a practical note, the amp I just sent you has the load line set to accommodate 4 to 16Ω. As you go up towards 16Ω however the performance alters a bit. I included a pair of 22Ω resistors to use in parallel with your speakers if they are 16Ω loads. They may or may not make a difference with any such speaker but they are there to try if you like. Just wire them across the output terminals. - np"

The plan was simple. Nelson wouldn't reveal any circuit details or specs until my comparisons and sonic comments were in the can. That way expectations wouldn't interfere with raw listening. In theory. In practice, c'mon. This was the latest in a series of high-performance amps. It introduced a new hi-tech output device that had cost Nelson a very pretty penny. Surely it would be demonstrably superior in some way, shape or form. Why otherwise bother. An unavoidable expectation thus preceded this encounter. My question wasn't really whether it'd be better. I was focused on how. Psychology is a bitch. One shouldn't pretend it away. Best to acknowledge its influence to openly navigate subjectivity. At least my framework of F5, J2 and M2 was solid. And to complete the picture, I'd ask Jon ver Halen for his parallel impressions if he was up for sharing in public.

Given the man's considerable buy-in costs to obtain these parts, cynics would predict a new luxo division for Nelson's 'kitchen table' range. Ring in the static induction transistors with statement case work. Ratchet up the price. Go a bit exclusive. Not here. Cynics will have to eat crow. "I'll get sufficient SIT traction in future Pass Labs products. I want for more people to be able to afford these amps. The case work and cosmetics will remain deliberately simple to focus on performance."

The SITuation: Cracking the proto open I spotted just two transistors per channel. To this techno peasant's eyes those looked suspiciously wired up in a Sakuma-style single-ended scheme of like drives like. Was this then a bona fide SET where 't' simply signifies a triode transistor?

The amp certainly had real thermal acceleration. Although I've never attached probes to measure actual dissipation, it's become customary to touch the heat sinks of the F5 or J2 past power up to determine when things are cooking to let the tunes loose. This one appeared to get toasty faster than previous samples in the range. And while it was still idling—giving me time to carefully contemplate what track to cue of for the maiden run—the machine proved as deathly silent as all previous FirstWatters (just what noise tube fanciers put up with becomes doubly dubious in such cases).