Gramophone Dreams

With the First Watt SIT-3: When the Nelson Pass–designed First Watt SIT-3 power amplifier clicks with a speaker, it presents recordings in a manner that has bones, core strength, and a natural way with vocal and instrumental timbre. One of the speakers the SIT-3 really clicked with was Harbeth's P3ESR 40th Anniversary Edition; see the first link in footnote 1 for details. The SIT-3 is an 18W, transformer coupled, single-ended, single-stage class-A amplifier that uses vertically stacked, static-induction field-effect transistors exclusive to First Watt. It uses no negative feedback and dances best with 6 ohm speakers like the P3ESR XD.

With the Harbeth P3s, the SIT-3 shaped and molded soundforms into something with chunk and a beguiling plasticity. This "molding" is something most amps don't do, but I wish more amps did, because it gives dimension and body to musical forms. The SIT-3 feels like it rolls off the topmost octave, but it doesn't. Instead, it presents performers and their instruments with so much flesh and bone that

I forget to notice the highs. With the P3s powered by the SIT-3, every recording venue seemed more voluminous than it did with the Parasound A 21+ or my Elekit 300Bs. With the 300Bs, the P3s show off an explicit transparency that makes it a fine speaker for choir and orchestra. The Parasound A 21+ expands the P3's soundspace, solidifies pianos, and emphasizes musical drama. The SIT-3 makes the P3s sound eerily natural and physically real in ways I have never experienced with other amps. This was a uniquely satisfying pairing.

The un-Corinthian Nelson
One of my sparrow spies told me that Harbeth's curiously named woofer–speaker stand combination, the Nelson, is regarded by its keepers as a visual pun—first noticed I presume after a few pints—on that famous Corinthian column topped by a statue of Admiral Horatio Nelson in Trafalgar Square. It could also reference one or more bits of less polite pub slang.

Costing $3490/pair and standing 31" from the speaker-platform on top to the tips of the cone-spiked feet on its base, the Nelson woofer uses the same Harbeth-made 4.33" (110mm; footnote 6) radial woofer as the P3s inside a grille cloth–covered tube that feels like cardboard—though the Harbeth website says the Nelson "features the latest composite materials, providing high stiffness with low mass," so presumably it's not actually cardboard. Either way, this tube serves as what Harbeth describes as a "bandpass enclosure."

I presume this woofer is loaded somehow and is firing down into and out of the Nelson's 4" high, 14" diameter steel base. A flat panel on the back of its round-caged bottom incorporates a receptacle for the wire-wart, 24V power supply for the built-in 50W class-D amplifier. A simple control knob permits users to adjust the woofer's level. "The Nelson's digital signal processing unit optimizes the crossover frequency, phase, and shape so the Nelson takes over seamlessly as the host speaker's bass rolls off."

This all sounds like website blah blah blah, but my listening impressions suggest that something unusually correct is happening phase-wise in the octaves on either side of the Nelson's 75Hz crossover point. The Nelson features a 5k ohm input transformer that, according to Harbeth's website, "presents virtually no load to the main amplifier." I am not sure how that works, but in use it felt as though the Nelson's load might be smoothing the P3's response.

With the Nelson's levels set at 11 o'clock in my 10' × 13' × 9' room, its palm-sized drivers flattened the P3's measured frequency response below 100Hz by raising the average volume in the octaves from 25Hz to 100Hz by as much as 9dB. The Nelson is said to extend frequency response down to ∼35Hz, ±3dB.

I am not an experienced subwoofer user, yet finding the best level in my room was quick and easy, and the result was a speaker that sounded larger and played smoother. Placing the Nelson + P3 in my room was also easy, as the P3ESR XD seems to play right no matter where I put it.

During my auditions, the P3/Nelson combos were 7' apart and 2' from the wall behind them.

After a week of listening, I got the point of Alan Shaw's latest invention: The Nelson adds bass weight in addition to some luxurious depth and atmosphere. That extra bass weight was obvious and welcome on Nils Frahm's Felt; on the first track, the bass actually shook my easy-to-shake floor. On the second, the soundspace became infinitely deep in a manner the P3 could not have done without the Nelson's help. On that same track, the loud sounds of the piano's action appeared, crackling with razor-sharp transients and microdetail. On the third track, I could hear Nils breathing. On the fourth, I could hear him whistling, and household noises coming from a room far behind him. I still had to sit close, but the voice this system projected felt full-range, elegant, and well-spoken.

Bore to stroke ratio: Compared to the P3 alone, the P3 + Nelson projected a taller energy field, wherein it seemed the woofer on the bottom made the location of the box on top less noticeable. That in turn made the presentation feel more of a piece than with the P3ESR XDs alone. This feeling of wholeness encouraged my left brain to remind me how the Nelson moved the geometric center of the P3's spectral balance down almost a full octave, allowing my mind to work less hard extrapolating for the missing bass octaves.

This was a different experience from adding a separately located subwoofer like the KEF KC62 or SVS 3000 Micro subs I reviewed. Adding those floor-woofers never let my mind relax completely because my audio-brain kept looking for the extra sound source. The Nelsons never revealed their locations, which caused me to speculate: Maybe I can't locate them because according to my in-room measurements the Nelson shuts off completely by 100Hz, and because, according to Harbeth's webpage, the DSP aligns phase at the crossover frequency.

Listening with Nelson, P3, and Parasound's A 21+: I imagine a lot of rock-steady Harbeth fans have discovered, as I did, that no matter how much Harbeth's P3s like 300B triodes, they light up recordings in a bolder, more articulate manner when connected to a more powerful solid state amplifier like Parasound's Halo A 21+. The tube glow is gone of course, but it is replaced by the depth and assuredness that 300W into 8 ohms can provide. For years now, the A 21+ has enhanced every speaker I've connected it to. I call it "a 10W amp with a 1000W power supply," because it plays sensitive speakers with such incredible charm.

Listening critically to the native-DSD download of Todd Garfinkle's 5.6MHz DSD recording of Sera Una Noche Otra Noche (M•A Recordings MA092A), and comparing it to the 24-bit/176.4kHz WAV file and then to the Red Book CD, focused my attentions on transient sharpness and perceived transparency. The DSD download presented an atom-level view of this recording's raw data where nothing is sharp or dull. Through the dCS Lina DAC with Master Clock, Todd's DSD file came out with a grainless density and a brilliant transparency.

In comparison, the demonstration-quality 24/176.4 WAV file displayed a different light-and-contrast structure. PCM's transparency was drier and more coolly lit. Transients in the WAV file seemed edge-sharpened compared to DSD and CD. The CD came through with the greatest body, slam, and texture, but this high punch factor was accompanied by a slightly thicker air, a slightly softer focus, and reduced transparency. With the Nelson woofer, Harbeth's P3ESR XD exposed these elusive differences more clearly than it did without the woofer. Adding Harbeth's bass column relaxed and clarified the P3 monitors in a manner that made all recordings easier to enjoy and scrutinize.

The Nelson with the Gold Badge: Standing 29" high, the Nelson places my Falcon Gold Badges 5" higher than they sit on my 24" Sound Anchor Stands. Because that's where they worked best with the P3s, I have the Nelsons and the Gold Badges sitting 22" from the speaker backs to the wall behind them; that's 11" farther out than I would usually have the Falcons. This is a not-insignificant repositioning of my reference speaker, so I listened for a couple days with the Nelsons powered off; the result was a lighter, bouncier, more transparent speaker. Resting on taller stands, the Falcons presented a leaner, cleaner 50Hz to 500Hz, which I reasoned might help them mesh with the Nelsons. And I believe it did.

I often say that I need the 75Hz to 300Hz octaves to be clean and well-sorted, because my LS3/5a's are famously wayward in that region. Adding a subwoofer won't make those two octaves clearer, but it can smooth out their frequency response. Which is precisely what the Nelson and its clever DSP did. The effect of this flattening was to smooth and sweeten the Falcon's voice and add body to its tone.

Nowhere was this extra body and sweeter voice more obvious than it was playing a Japanese flute and traditional dance album from 1968 (King Records LP SKM 29). This ultrahigh-fidelity recording of drums, shakuhachi flute, stringed koto, or biwa, occupied my room in a manner I can only describe as stunningly physical and true-to-life. That awe-inducing realism was dramatically reduced when I turned the Nelson woofer off.

In sum
Harbeth's P3ESR XD sounded exactly as I expected it would: more finely detailed and transparent than my memories of the 40th Anniversary edition I used for several years.

The big news of this 86th Dream, though, is the Nelson woofer's ability to add an octave of bass and blend invisibly with Harbeth's P3ESR XD, and my Falcon LS3/5a. I did not predict that. The Nelson enabled both speakers to image from floor to ceiling and deliver a mesmerizing, precisely rendered spectacle that even LS3/5a purists like me could embrace.

Adding the Nelson subwoofer stand to Harbeth's P3ESR XD created an entirely new, longer-wheelbase, smoother-riding, fuller-sounding speaker, a must-audition for Harbeth P3 and LS3/5a aficionados.

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Footnote 6: Harbeth specifies the driver size as 110mm, equivalent to 4.33", but also refers to it as a 5" drive unit.