First Watt SIT-3 power amplifier Page 2

The illusion of an accordion suspended between my speakers seemed whole and believable. By that I mean that I believe the chief difference between live and reproduced music lies chiefly in the continuity of timing and phase relationships between music's fundamental tones and their expanding harmonic series. My personal observations suggest that negative feedback mutates these prime relationships while adding its own higher-order harmonic content. The First Watt SIT-3 seemed to preserve the geometry of the original harmonic relationships better than any amp I can remember, and thus made instruments sound quite real.

Listening with Harbeth Monitor 30.2 loudspeakers
Harbeth's little P3ESRs danced gingerly with the SIT-3. But the bigger Harbeth Monitor 30.2s were heavier on their feet. The piano of Hélène Grimaud, as she played the Mélodie from Gluck's Orfeo ed Euridice on her collection Perspectives (16/44.1 FLAC, Deutsche Grammophon/Tidal), had something close to perfect tone and good weight—but there was a hesitancy of timing, a slight dulling of textural detail, and a sense of distance that made me think that the First Watt was under-powering the medium-size M30.2s, which prefer Rogue's 100W Stereo 100 but also play super-superbly with Pass Labs' 25W XA25.

Listening with Zu Audio Soul Supreme loudspeakers
In the vestibule of Nelson Pass's house was a pair of red Zu Audio Druid loudspeakers tht Pass had brought back from the 2018 Burning Amp Festival. Pass knows Sean Casey, Zu's founder and engineer, and at audio shows Casey makes great sounds with one or another of his speaker designs driven by Pass Labs amps. I therefore assumed that the SIT-3 would drive my Zu Soul Supremes with easy-rolling ease and super dynamics. I was wrong. The Soul Supremes, specified as having a sensitivity of 101dB/W/m and a nominal impedance of 16 ohms, sounded mushy and muffled with the First Watt. Not dynamic. My friend Sphere was with me, and we were dumbfounded. As we listened, Sphere sent Pass an e-mail. Right away came the reply: "Tell Herb to shunt a 16-ohm/10W resistor across the Souls' binding posts." Which I did.

The shunt resistors accomplished several things. Primarily, they reduced the Souls' nominal impedance to about 8 ohms, and their minimum impedance to closer to 4 ohms. They also lowered the impedance peaks and reduced the phase shift. Most important, the sound changed from mushy and muffled to vivid, clear, and crisply detailed. The simple addition of a resistor had allowed the Soul Supremes to deliver a charming, relaxed, naturally focused sound that satisfied with all types of music.

When I told JA about this experience, he told me he'd written an app that would show us what the impedance curve of the newly shunt-resistored Zus would look like. When I saw the graph he'd generated with the app, I laughed. The Zu's impedance characteristic now looked a bit like the Harbeth P3ESR's. And, surprise surprise, suddenly the Soul Supremes sounded a lot like the Harbeth P3ESRs, with basically the same texture and tone character—but, of course, the Zus could move more air and play much louder.

Listening with DeVore Fidelity Orangutan O/93 loudspeakers
The DeVore Orangutan O/93s (10 ohms, 93dB/W/m) really liked the First Watt SIT-3 and Sonny Rollins. "God Bless the Child," from The Essential Sonny Rollins: The RCA Years (16/44.1 FLAC, RCA/Tidal), sounded so simple and dreamy in its sonic essence; that essence was enhanced by the attractive burnished tones emanating from the DeVores.

"God Bless the Child" was precisely painted, with subtle but audible hesitations and pregnant, vibration-filled pauses. I immediately heard the expansive size of the soundstage produced by the O/93s. Bob Cranshaw's bass had never before sounded so big or more real. Rollins's tenor sax, Jim Hall's guitar, and Ben Riley's drums generated large, deep, perfectly toned sounds, the likes of which I'd never before heard from the DeVores. Nor had the Orangutans ever imaged so precisely. Five-foot shadow figures stood tall between the '93s' polished boxes—and those boxes "disappeared" more completely than they usually do. Together, the O/93s and SIT-3 made memorable magic. If you already own O/93s, this amp is wagging its tail for your attention.

Listening with Falcon Acoustics LS3/5a loudspeakers
I listened closely to the SIT-3 driving Falcon's LS3/5a minimonitors. I worried that the 15-ohm Falcons might be a replay of the 16-ohm Zu Soul Supremes, and they did. My beloved LS3/5a's didn't sound mushy and muffled, just noticeably distorted through the midband. So I hauled out some 16-ohm resistors, shunted the Falcons' speaker terminals as I had the Zus', and voilà! The distortion mostly vanished. But the Falcon–First Watt pairing still wasn't singing or dancing. It sounded stiff and gray. Remembering how much I'd liked the First Watt J2 amp with the high-impedance Falcons, I removed their 16-ohm resistors and swapped in the J2. No purple prose required: The J2 plus Falcon LS3/5a's is a truly natural, breathy-voices, perfect-midrange, made-for-each-other, guaranteed-pleasurable combination. But I can't recommend that you mate the Falcons to the J2's stablemate, the First Watt SIT-3.

Listening with Magnepan .7 loudspeakers
I'm always 100% happy when the Magnepan .7s ($1400/pair) are in my system, but I never imagined they could sound this beguiling. The First Watt SIT-3 forced me to appreciate the Maggies a lot more. It played Mississippi Fred McDowell's You Gotta Move (16/44.1 FLAC, Arhoolie/Tidal) and Skip James's Blues from the Delta (CD, Vanguard 79517-2) with riveting verity and full-tilt boogie via these insensitive, 4 ohm, quasi-ribbon panel speakers. Every pick or pluck of string grabbed my attention and focused it on these artists' phenomenal imaginations. James and McDowell were incomparable guitarists, and any proper hi-fi will keep the listener's mind on how and what they're doing with their strings. The SIT-3 and Maggie .7s put me in the room with the microphones, watching these masters' hands and following their grooves.

The SIT-Maggie combo generated a distinctive, liquid, ribbon-tweeter clarity that also flattered sopranos in a way not bested by any other amp-speaker combination I've tried.

Voices and instruments were no less there than they were with the Pass Labs XA25 or the Bel Canto Design e.One REF600M, and that's saying a lot—those amps make really SOLID sound with the Magnepan .7s. Wilder still, the SIT-3 generated more relaxed, natural detail and a bigger, better-mapped soundstage than I'd previously thought possible with these humble planars.

Summary 1
Three very different loudspeakers proved to be compatible with the First Watt SIT-3: the Harbeth P3ESR, the DeVore Fidelity Orangutan O/93, and the Magnepan .7. All were enjoyable, perfect, magical, 100% exciting matches for the SIT-3.

Summary 2
Did the First Watt SIT-3 sound like a single-ended-triode tube amplifier? Not really. It didn't sound like any other amp I know, either. I compared the SIT-3 directly to my Line Magnetic LM-518 IA tubed integrated amp ($4450) and found it sounded noticeably less vivid. The LM-518 IA was clearly more airy and extended in and descriptive of the top two octaves. However, the SIT-3's midrange and bass were cleaner, fuller, more textured, more rich in information. The SIT-3 produced denser, more specific images.

Nelson Pass is that rare type of audio-engineering maverick who measures and listens with equal facility. He's not wasting his time and your money trying to cram a thousand crap watts into a marketing department's bling box. He does not believe that all measurable "distortions" are, willy-nilly, enemies of high-fidelity sound. Instead, he focuses his considerable intelligence and resources not only on reducing various types of distortion, but also on studying the essential natures of those distortions. He uses blind listening and ABX testing to understand how experienced listeners perceive distortion, and the role that distortion might play in helping our brains reconstruct the original musical event. In the SIT-3, Pass has allowed a carefully prescribed dose of negative-phase second-harmonic distortion to appear at low levels, with a tiny touch of third-harmonic distortion at higher powers. The second harmonic, he says, "fosters an illusion of expanded space and image specificity; the third appears to improve dynamics."

I consider this type of thinking radical intelligence, and my experience with the First Watt SIT-3 suggests that it is among Nelson Pass's finest achievements. It's too bad that SemiSouth went south; it's too bad Pass will make only 250 SIT-3s; it's too bad that so few audiophiles will ever experience its unique, information-rich pleasures; and it's too sad that even fewer audiophiles will comprehend the 100 years of engineering wisdom distilled by Nelson Pass into this modestly priced masterpiece. Bravo, Maestro!

Pass Laboratories Inc.
13395 New Airport Road, Suite G
Auburn, CA 95602
(530) 878-5350

tonykaz's picture

Off to bad start?, not quite click-bait but compelling.

Well, ok, this seems a thinking man's Amplifier with plenty of personality.

$4,000 while supplies last.

Tony in Michigan

ps. how'd this thing do with Steve G's Klipsch "loud"-speaking" speakers?

John Atkinson's picture
tonykaz wrote:
how'd this thing do with Steve G's Klipsch "loud"-speaking" speakers?

The answer to that question will be found in the April issue of Stereophile.

John Atkinson
Editor, Stereophile

Ortofan's picture

... the level of second harmonic distortion is barely -45dB below the fundamental can be deemed to "preserve the geometry of the original harmonic relationships better than any amp I can remember"?
Wouldn't an amp that adds as little harmonic distortion as possible, such as the Benchmark AHB-2, do a far better job of preserving the geometry of the original harmonic relationships?

mememe2's picture

When Herb writes " I felt I could measure the added reverb. I thought I could feel the air moving in and out of her instrument.". I wondered why he didn't include an actual measurement to back up this "feeling". Next his thought that he could "feel the air moving in and out of her instrument" sounds like pure unadulterated mystical hyperbole. Really? Less hyper-hyperbola please.

johnnythunder's picture

music "feels and sounds" to the individual reviewers, you shouldn't be reading Stereophile or the Absolute Sound, or Hifi News and RR etc. etc. That type of description is WHY we read these publications and websites. Sometimes light is shed on the subjective response by John A's fact checking measurements but not all of it. So we take these written feelings and if they sync with how you like to feel and hear recorded music you add said equipment to your list of pieces to audition. If you want a measurement to back up every comment, you're wasting your time reading audio reviewers. In fact, that's like asking for a chemical analysis of every morsel of food should a food magazine say you're wasting your time with $5 a bottle Extra Virgin Olive oil compared to $20a bottle. I'm sure there are people who feel that the more expensive olive oil is a waste of money" as "taste" is a subective thing.
Ditto with more expensive wines. "Sound" familiar ?

mememe2's picture

According to johnnythunder readers of the mags he quoted only want how a product "feels and sounds With that as the ultimate criteria for reading those mags why do the measurements (sometimes ) appear at the end of the reviews? And let's just do away with the technical descriptions as they don't really matter because they tell us nothing informative about how the gear under review will feel or sound like. Maybe -to shore up the how it "feels and sounds like" we should, at the very least insist on All reviewers to post a recent audiologists measurement (the bane of those that worship at the alter of subjectivity)) of the state of their hearing.

Bertie Bucket's picture

If this was a Chinese amp I'm pretty sure the usual suspects would be all over those measuremets pointing out it must be garbage.

As an aside, relaxing the definition of clipping....why not relax the definition of surface resonance on speakers that have a lot of resonance or any of the other parameters. They are meant to show a standardised approach otherwise, what's the point of them?

This amp bombed producing 8.4W at 1% THD distortion.

The fact amps like these garner a cult following says more about marketing and human fallacies than anything.

gyokuro_jp's picture

Dear Mr. Reichert,

you write about the FirstWatt SIT-3:

" I compared the SIT-3 directly to my Line Magnetic LM-518 IA tubed integrated amp ($4450) and found it sounded noticeably less vivid."

I want to understand it correctly, what amplifier sounds noticeably less vivid?

Thank you for your reply and kind regards

Herb Reichert's picture

my less-than-clear sentence. I just re-listened to both amplifiers and the First Watt SIT-3 is plainer-sounding less contrasty and therefore less "vivid" than the 845 tube amp. . .but! The biggest difference between the two is: the Line Magnetic is happier with a wider range of speaker impedances.

peace and pumpkins,


davip's picture

Am I seeing a pattern here? The reviewer thinks that this is " of the two or three finest-sounding amplifiers I've heard anywhere, at any price". In fact, the only amplifier he finds that handily does better is the Line Magnetic LM-518 that is his Reference (and that he also reviewed, here: The common measurable aspects of the two? Neither can produce more than 1-8W for 1% THD, both laced with high amounts of 2nd- and 3rd-harmonic distortion. Don't get me wrong -- I uniformly appreciate the difference between the audio-reality of vinyl and the cardboard pastiche that is digital, and I know which of these measures 'better', but this reviewer's apparent liking of the euphony of harmonic distortion-sauced amplifiers colours -- literally -- the basis of a review that purchasers may then use as a basis for forking-out 1000s of $. My 30W Nytech CA252, whose audio I adore, routinely clips on musical peaks into an 88 db/W/8 ohm load at sane listening levels. What use then are amplifiers that produce only 3-30% of that power (and for 30x the price to boot)? Fine for accordion music and 'audiophile female vocals' perhaps, but play Peter Gabriel IV (that will also be in every audiophile's musical collection) through either of these devices at anything other than table-radio levels and neither would be fit-for-purpose as amplifiers at all, much less high-end audiophile ones... To re-use the reviewer's own re-quote, "...really not suitable for serious audiophile consideration". Indeed, in chiding his reviewer-friend's objectivity for his using his own speakers to review amplifiers, Herb's reference amplifier cannot produce more than 1W of undistorted output, and for the < 0.1% THD that most would regard as a reasonable threshold can produce no output at all by JA's measurement. How many audiophiles listen to the accordion music that figured so prominently in this review, and how many listen to rock? How meaningful is such a review, therefore?

Murphbass's picture

Mr. Reichert-

Would you care to share your experiences contrasting the Primaluna vs Rogue preamps when used with the SIT-3 and .7s (the heart of my system)? I currently use the Mytek Brooklyn Bridge for streaming/DAC duties as well as the phono preamp but am lacking in gain. I would like some coloration from the pre as well.

Your writing was a big factor in my purchase of this amp and the Maggies, and I'm very happy with both. Thanks!