Recommended Components

A

Ayre Acoustics AX-5 Twenty: $12,950
In 2013, AD described the original Ayre AX-5—a $9950 integrated amplifier built around a recently rediscovered configuration of bipolar transistors known as the "diamond" circuit—as "one of the three best, most musical, most human-sounding solid-state amps I've ever heard." Then, in 2015, Ayre debuted a new version, the AX-5 Twenty—a nod to the company's 20th anniversary—promising even better sound. The AX-5 Twenty is built into the same foursquare aluminum case as the AX-5, and is controlled by the same performance-optimizing Variable Gain Transconductance (VGT) volume-control system—but the Twenty incorporates Ayre's new Double Diamond output, claimed to run cooler (which AD verified) and to offer slightly more power (though the 125Wpc rating remains). This time out, AD got a little pissy about Ayre's user manual and the amp's "pointlessly complex" setup procedure, but was otherwise smitten: He delighted in a sound that was "slightly sweeter" than the original AX-5's. Stringed instruments, he said, were "reproduced with color, body, scale, melodic and rhythmic drive, and believable spatial presence." AD concluded that "the AX-5 Twenty is inarguably . . . more compelling than its predecessor." Although he raised an eyebrow at the 30% ($3000) price increase over the original, AD commended Ayre for allowing AX-5 owners to have their amps upgraded to Twenty status for the same price. (Vol.38 No.8 WWW)

Bel Canto Design Black amplification system: $50,000
Tempting though such a classification may be, the Bel Canto Black is more than just an integrated amplifier. This three-box system comprises a sort-of preamplifier (the ASC1) and a pair of sort-of monoblock amplifiers (the MPS1), the latter operating in class-D, for 300Wpc into 8 ohms or 1200Wpc into 2 ohms. The Ethernet-ready ASC1 can be controlled with an iPhone app; it provides a brace of digital inputs, and via ST-optical connections feeds the MPS1s digital signals at their native resolutions, up to 24-bit/192kHz and DSD64. The ASC1's single pair of analog inputs (RCA) address an internal 24/192 DAC: Everything that goes through the ASC1 does so as a digital stream, eligible for tailoring by a variety of user-selectable digital filters. (The MPS1s also offer analog inputs.) In his listening tests, MF found the Bel Canto Black to offer "the most compelling digital sound yet," and to embody the best-yet implementation of class-D technology: "[H]ere, finally, is a class-D product that, though sounding definitely different from the older technologies, makes a strong case for equality." JA declared that he was "very impressed by the Bel Canto Black, especially with its behavior as a D/A converter that is effectively capable of driving loudspeakers." From his own listening tests, described in a Follow-Up, JA noted the Black's ability to present spatial and sonic detail. Comparing the Bel Canto to the recently reviewed Ayre Acoustics KX-R Twenty preamp and MX-R Twenty mono amplifiers, JA wrote: "If the Ayre system was more simpatico with the heart, the Bel Canto Black appealed more to the head." (Vol.38 Nos. 7 & 10 WWW)

Classé Sigma 2200i: $5500
See TJN's review in this issue.

GamuT Di150 LE: $12,990
See KM's review in this issue.

LFD LE V: $4495
Dr. Richard Bews, proprietor of England's LFD electronics, has once again upgraded his and Dr. Malcolm O. Hawksford's original integrated amplifier, the 65Wpc LE (née Mistral): a perennial ST favorite, owing to its complete lack of convenience or "luxury" features that degrade sound and add expense. To those ends, all iterations of LFD's solid-state amp have lacked balance and tone controls, headphone jacks, extra sets of speaker outputs, digital displays, and, especially, remote controls. The LE, which Dr. Bews builds in small batches, provides five line-level inputs (but no phono section), and is made with only the highest-quality parts, some vintage (NOS), some custom-made. According to ST, the new LE V—whose improvements all seem to arise from a combination of sturdier casework and more refined parts—"is a showstopper. I mean that literally. I didn't want to write; I wanted to listen." Compared to the LE IV, which ST owns and loves, the LE V represents "a substantial improvement. Everything just fit into place: harmonics, timing, resolution." Quoth he: "Buy your LFD LE V today." (Vol.37 No.7)

Line Magnetic LM-518IA: $4450
An original design from a Chinese company that also re-creates classic Western Electric audio gear, the all-tube Line Magnetic LM-518IA is the rare modern integrated amplifier that combines a single-ended output stage with thoriated-tungsten (ie, bright-emitter) output tubes and a tube-rectified voltage rail. The LM-518IA provides three line-level inputs (all RCA) and produces up to 22Wpc into 8 ohms. Tube bias is user-adjustable—but, to HR's disappointment, there is no balance control or mono switch. That said, the amp's "vital energy," among other qualities, has earned it an especially hallowed place in his system: "It is musically alive and vigorous. It plays music with rare charm and sensitivity." even the SET-skeptical JA was charmed: "For such a design, it offers high power." (Vol.38 No.10, Vol.39 No.10 WWW)

Mark Levinson No.585: $12,000
With twice the output power, twice the number of digital inputs for its built-in DAC, and a price tag that's twice as high, the Mark Levinson No.585 integrated amplifier handily exceeds its predecessor, the No.383. (Perhaps they should have called it the No.766?) The class-AB No.585 is advertised as delivering 200Wpc into 8 ohms, and its DAC, which offers resolution up to DSD256, includes an asynchronous USB input alongside two (S/PDIF) RCA inputs, two TosLink inputs, and a balanced XLR jack for AES/EBU. Of its four line-level inputs, one is balanced (XLR). Driving LG's Quad ESL-989 electrostatic loudspeakers—and, via its line-level output, a Tannoy TS2.12 subwoofer—the No.585 impressed him with its "sonic purity and ergonomics." LG declared that, while listening to a recent recording of Beethoven's Symphony 7, "I was reminded of being surrounded by the music, the clearly defined sounds of the instruments, and the ambience of Avery Fisher Hall." Noting, among other things, that the No.585 exceeded its manufacturer's power specs, managing 250Wpc at 8 ohms and 390Wpc at 4 ohms, JA stated that it "offers impressive measured performance." (Vol.38 No.12 WWW)

Moon by Simaudio Evolution 700i: $14,000 ★
Robustly built of thick, ultrarigid aluminum, the 700i is a fully differential dual-mono design rated to deliver 175Wpc (190Wpc at actual clipping), running in class-A up to 5W and in class-AB thereafter. Its output stages are powered by six bipolar transistors per channel for a wide bandwidth and low noise floor, while its "zero global feedback" design works to boost the speed of the signal response and eliminate intermodulation distortion. Though it couldn't match the Krell FBI's transient speed or deep-bass extension, the 700i had a full-blooded, dynamic, seamless sound marked by vivid tonal colors, harmonic integrity, and a strong sense of rhythm. With the 700i, "I found myself drawn deeper into the music," said FK. (Vol.34 No.3 WWW; see also FK's Moon Evolution 860A review in Vol.38 No.8 WWW)

Moon by Simaudio Neo 340i: $5800
The 100Wpc Moon Neo 340i is among the growing number of integrated amplifiers that can be upgraded with a plug-in DSD-ready DAC ($900), a plug-in phono stage with MM and MC inputs ($400), and true-balanced XLR inputs ($350). You can get all those options at the start by buying the version Simaudio calls the D3PX ($5800). HR reviewed the latter and especially enjoyed the amp's performance with his Magnepan .7 speakers: "The Simaudio's apparent speed and transparency tamed the Magnepans' inherent sweetness to the point where the .7s began to sound like the high-resolution transducers they are." HR also singled-out for praise the "ridiculously good" performance of the Neo 340i's MC phono inputs, loading characteristics of which are user-adjustable by means of internal jumper blocks, although he noted that his Zu Denon DL-103 cartridge "plays more naturally and in a more relaxed manner into 470 or 1000 ohms than into either of the 340i's choices of 100 ohms or 47k ohms." Reporting from his test bench, JA discovered lowish unbalanced line-level input impedance (7200 ohms at 20Hz and 1kHz), and heatsinking that "isn't adequate for sustained use at high powers"—but otherwise gave this Moon a clean bill of health. (Vol.39 No.3 WWW)

Musical Fidelity Nu-Vista 800: $12,999
The latest in a line of Musical Fidelity products distinguished by their use of nuvistors—miniature small-signal vacuum tubes of such extreme durability that they're often hardwired into circuits—the Nu-Vista 800 is a solid-state integrated amp in which thermionic devices influence both sound and vibe. (The Nu-Vista 800's four nuvistors are illuminated from below and visible from above.) This 330Wpc powerhouse has five pairs of bipolar transistors per channel and provides five line-level inputs, one of them balanced. In addition to describing it as Musical Fidelity's "best-looking product, ever," MF praised the Nu-Vista 800 for its "wholeness and consistency of sound" and for being "relaxed and suave, but not at all soggy or gauzy." And while noting that the amp didn't extract from his recordings the last drop of crispness or detail, MF praised its consistently beautiful sound: "The Nu-Vista 800 drew me in." In measuring the Nu-Vista 800, JA discovered a signal/noise ratio that was "a little disappointing," and very slightly less power output (310Wpc into 8 ohms) than is specified, but was otherwise impressed. (Vol.38 No.11 WWW)

Parasound Halo Integrated: $2495 $$$
Parasound's Halo offers 160Wpc from its bipolar output section—JFETs and MOSFETs are pressed into service elsewhere in the amp—plus a list of convenience features that includes: a dedicated subwoofer output with its own variable high- and low-pass crossover filters and front-panel level control; a 32-bit DAC with USB, coaxial, and optical inputs; a discrete headphone amplifier; an MM/MC phono stage; and six line inputs (one balanced, five unbalanced). HR particularly praised the "easy, intimate realism" of the Halo's phono stage, as well as the "great boogie" factor of its DAC and the amp's overall "easy flowing, mostly smooth, and decidedly mellow" personality. This was not to take away from the Parasound's musical incisiveness: "The Halo played tunes and sang songs as if they mattered," wrote Herb. JA wrapped up his measurements by observing that the Halo Integrated "is a well-engineered, well-performing product." (Vol.38 No.11 WWW)

Pass Labs INT-60: $9000
The solid-state INT-60 integrated amplifier provides 60Wpc in class-AB, about 30W of which is in pure class-A. (To help confirm that, the needle-and-scale meter that dominates the amp's front panel indicates when the INT-60 slips from one mode into the other.) The Pass has four line-level inputs, two of which offer a choice of single-ended (RCAs) or balanced (LR) jacks, the remaining two offering single-ended only. As shipped from Pass Labs, the INT-60 has 29dB of gain, which can be bumped up to 35dB by removing a pair of internal jumpers. The INT-60 especially impressed HR when he tried it with Zu Audio's Soul Supreme speakers, seeming to mitigate their "extra energy" and rendering their typically lean bass performance "less lean, more muscular, and BIG." And HR found that "the Pass Labs INT-60 drove the [Magnepan] .7s with more subtle magic, slam, and lush joy than I'd previously heard from these speakers." Writing from his test bench, JA noted the Pass's higher-than-specified power output and observed that it offered "respectable measured performance," though the tendency of the INT-60's distortion signature to shift from predominantly second to predominantly third harmonic as the signal frequency rises gave him pause. (Vol.39 No.12 WWW)

PrimaLuna DiaLogue Premium HP: $4399
PrimaLuna's DiaLogue Premium HP employs a total of eight power tubes—EL34s are standard, although the user can substitute a variety of other power pentodes—to produce 40Wpc in triode mode or 70Wpc in Ultralinear mode. (On-the-fly switching between modes can be performed with the DiaLogue Premium HP's remote handset.) Additional features include a newly designed, six-tube front end; the "highest-end" implementation yet of PrimaLuna's Adaptive AutoBias circuit; and an all-tube headphone amp. RD, a fan of the company's earlier ProLogue Premium, found that the new amp provided higher power with no loss of finesse, and declared, "PrimaLuna had taken a major step forward in amplifier performance." JA's measurements indicated that "PrimaLuna's output transformers are of excellent quality." Distortion wasn't the lowest JA has seen, but, "fortunately, the distortion is heavily second-harmonic in nature in both modes, even at low frequencies." He concluded that, "overall, the PrimaLuna DiaLogue Premium HP measures well for a design using push-pull pairs of EL34 tubes." RD summed up: "$4199 for an integrated amp of the DiaLogue Premium HP's level of performance represents excellent value." (Vol.37 No.12 WWW)

Vinnie Rossi LIO: $7750 as tested
Vinnie Rossi, of Red Wine Audio, designed the LIO integrated amplifier around his unconventional PURE DC-4-EVR power-supply technology, which powers the electronics using two rows of series-wired ultracapacitors: one provides pure DC while the other is being charged, those roles alternating every few minutes. The LIO is modular: The buyer adds to the combination of case and power supply—a $1995 product that, by itself, cannot pass a music signal—his or her choice of volume-control module, input-selection module, line stage, phono stage, D/A converter, headphone amp, and power amp, prices and options for which are too numerous to list here. HR was charmed: "Right out of the box, the Vinnie Rossi LIO played music that flowed smoothly and silkily." He noted in particular the amp's "detail, drive, and forward momentum." HR's verdict: "If there is a more innovative and musically satisfying integrated amplifier than the Vinnie Rossi LIO, I have yet to experience it." JA's measurements revealed "good to excellent" performance from the LIO's volume-control, phono-preamp, and digital-audio modules, but uncovered problems such as low-level spuriae at 60Hz, unexpected bumps in the noise floor, power output into 8 ohms that failed to reach the 25Wpc spec by 8W, and too high a level of second-harmonic distortion for his comfort. (Vol.38 No.9 WWW)

Woo Audio WA5: $5899
See "Headphones & Headphone Accessories."

B

Allnic T-1800: $7490
From Korean manufacturer Allnic, known in audiophile circles for their single-ended-triode (SET) power amplifiers, comes this push-pull pentode integrated amp. The T-1800 has two EL34 output tubes per side, operated in Ultralinear mode to produce 40Wpc. The T-1800's line stage is passive—still, AD described the amp's overall gain as "abundant"—and offers as inputs four pairs of RCA jacks and one pair of XLR sockets. Source selection is by means of electronic switching, the volume control is a 41-step silver-contact attenuator switch, and the output section is autobias. AD thought that the T-1800 delivered tight, well-controlled bass—if with less "power and gravitas" than his Shindo EL34 monoblocks—and generous treble extension without sounding "bright or even bright-ish." He was dismayed by the sound's relative smallness of scale, which he attributed to the amp's use of global feedback, but said that "the T-1800's flaws are more than merely outweighed by its strengths: They are overwhelmed." Those strengths are good drive, color, texture, and openness of sound. (Vol.38 No.11 WWW)

April Music Aura Note v.2: $2500
The Aura Note V2 is a compact and sleekly styled integrated amplifier (125Wpc) with built-in CD player, USB DAC, FM tuner, Bluetooth receiver, and headphone amp. Its USB DAC, addressed by a USB Type A socket on one side of its casework, is good to 192kHz—it uses a 24-bit Cirrus Logic D/A chip—and its class-D amplifier output section uses ICEpower modules supplemented by a switch-mode power supply. The Aura Note V2's playback of CDs had "color and clarity, spatial presence, and a good sense of momentum and flow," according to AD, though its amplifier lacked a bit of texture and richness when compared to the best. He also noted some harshness on extreme peaks when using an outboard phono section into the Aura's line-level input. All in all, AD concluded, "the V2 offers a generally very good musical and sonic experience." Writing from his test bench, JA noted that the Aura Note V2's CD player exhibited one of the highest levels of tolerance of defective discs he's ever observed, but also found that its Aux inputs could be overdriven with input signals greater than 3.3V, thus underscoring the need for caution when matching a phono preamp and cartridge to this otherwise recommendable all-in-one box. (Vol.39 No.4 WWW)

Cambridge Audio Azur 851A: $1999
First cousin to the Cambridge Azur 851D DAC, the Azur 851A integrated amplifier provides 120Wpc into 8 ohms, two balanced inputs (XLR), eight unbalanced line-level inputs (RCA), and the rare luxury of bass and treble tone controls. HR wrote that he could best describe the sound of the Azur 851A as "relaxed and enjoyably colorful, in a class-A triode sort of way. It sounded more naturally toned and weighty than my Creek 3330 or my Line Magnetic LM-518IA, and showed none of that off-putting grayness or brittleness often heard in low-priced, high-powered amps." In his measurements, JA discovered that the amp's right-channel performance was not in keeping with that of the left channel—although he suggested that the right channel's relative shortcomings were inaudible. His conclusion: "Assuming that the less-good performance of its right channel was a sample-specific fault, Cambridge Audio's Azur 851A is a well-built amplifier that offers a lot of power with very low distortion at an affordable price." HR's last word: "a versatile and extraordinarily musical cornerstone on which to build a truly enjoyable high-end system that can play all types of music with righteous aplomb for little cost." (Vol.38 No.2 WWW)

Cary SI-300.2d: $5995
In years past, when the number 300 appeared in a Cary Audio product name, you could bet it referred to a certain low-power output tube; today, in the context of Cary's SI-300.2d integrated amp, it stands for output power—as in 300Wpc (into 8 ohms). The solid-state SI-300.2d also incorporates a DAC that offers PCM to 384kHz and DSD up to DSD256. (DSD is handled natively, except where the signal is streamed from a Mac—in which case DSD is handled as DoP.) The option of upsampling PCM to various higher sampling rates or to DSD is provided, although it does not apply to the Cary's USB digital input. In his listening tests, KM remarked on the SI-300.2d's "extreme resolution, and never at the cost of tonal richness or spatial substance." KM described the Cary's sound, with Elac B6 loudspeakers, as being "as transparent as a fall sky, and as tonally even-keeled as I've heard in my nearfield setup," and concluded, "this was not the sound of your father's Cary tube amp." JA's test-bench findings were a decidedly mixed bag: "The amplifier itself is a straightforward, competently engineered" design, he wrote, but he found some irregularities in the performance of Cary's DAC, describing its upsampling behavior, in particular, as "perverse." (Vol.39 No.12 WWW)

Creek Audio Evolution 100A: $2195
The top-of-the-line amp from UK-based Creek, the new Evolution 100A integrated operates in class-G: A pair of Sanken Darlington transistors, biased for class-AB, do the honors up to 25Wpc, beyond which an additional pair of transistors kicks in, for 110Wpc total into 8 ohms. Of its five line-level inputs (RCA), one can also be addressed as balanced (XLR), while any of the remaining four can be upgraded with plug-in DAC, AM/FM tuner, and phono-stage modules. HR enjoyed using the Creek's Ambit tuner ($250), and praised the "clean, open, extended highs" of the amp's optional Ruby DAC module ($599), which handles 24-bit/192kHz inputs via its coax and TosLink S/PDIF inputs, and 24/96 via USB—though he felt the merely "good" Sequel Mk.2 moving-magnet phono-stage module ($200) wasn't up to the DAC's level of quality. Considering the 100A's amplification talents, HR praised it for playing a great variety of music in a "straightforward, exciting, satisfying way." Apart from some front-panel control glitches that might have been specific to "this well-traveled review sample," JA found that the Evolution 100A "measured quite well." (Vol.38 No.7 WWW)

Croft Phono Integrated: $1895 ★ $$$
Croft's 45Wpc Phono Integrated combines in a single package the company's Micro 25 preamplifier and Series 7 power amplifier to create a hybrid integrated in which line- and moving-magnet–compatible phono-stage gain is provided by ECC83 vacuum tubes, output power by transistors. In addition to its phono input, the Croft has three analog line inputs, but offers no remote control, digital inputs, headphone jack, or upgrade paths for USB connectivity. Apart from a small circuit board containing the bipolar timer and relays, the Phono Integrated is hand-wired, point to point, with neatly made solder joins and Bakelite terminal strips. AD liked the Croft's dual-mono volume controls, SM not so much. They agreed, however, that the Croft's sound was extraordinary: smooth, coherent, open, naturally detailed, forceful, physical, and dynamic, with a great sense of space and an expert ability to drive a beat forward. "If I were a designer or builder, this is how I would do the thing. If I were buying in this price range, this is the one I'd choose," raved AD. On JA's test bench, however, the Croft exhibited a nonflat RIAA response and high levels of harmonic and intermodulation distortion. According to ST, "the sound of the Phono Integrated was musical in a way that very few hi-fi components are." Apart from noting this model's 1970s-style cosmetics ("A pox on cosmetics!"), minimalist conveniences ("A pox on convenience!"), and slightly plump bass, ST declared the Croft "one of the best integrated amplifiers I have ever heard." (Vol.36 No.10, Vol.37 No.5 WWW)

Heed Audio Elixir: $1195 $$$
Heed, pronounced hid, is a Hungarian manufacturer whose generally affordable solid-state amplifiers feature deliberately non–direct-coupled output stages; indeed, Heed suggests that an amp with output capacitors—which they call translator capacitors—is better suited for "the stress-free generation of air-pressure changes [into] the sound we hear." Whether for that reason or not, KM was mightily impressed with this 50Wpc, MM phono–equipped integrated amp, being "immediately struck by the Elixir's superb sense of flow. The Elixir portrayed dynamic swings with a natural and effortless musicality." Ken's conclusion: "That so much amplifier is available for $1195 should have music lovers dancing, unclothed and unhinged, across fields and meadows, melodies on their lips, as creatures great and small join them in song." JA's measurements uncovered a bit of RIAA error in the phono section—associated with "a slightly rich balance"—and notably low power into a low-impedance (2 ohm) load, but noted that the Elixir's distortion signature "will also render it easy on the ear." (Vol.39 No.11 WWW)

Hegel Music Systems H160: $3500
The Norwegian-made Hegel H160 swims against technology's tide with an output section based on discrete bipolar transistors operated in class-AB, rather than the increasingly common class-D devices. The H160 is specified as offering 150Wpc into 8 ohms, and its features include a front-mounted 6.3mm headphone jack—a first on a Hegel amp—plus USB, coaxial, optical, and Ethernet digital inputs, these addressing an internal DAC whose measured performance JA described as "workmanlike." Despite his disappointment that the H160 offered only a single unbalanced analog input alongside its single balanced input, HR warmed to its "ardent and visceral" sound, and praised its playback of recorded voices as being "striking in its naturalness." JA's measurements included the observation that thermal stressing brought about a temporary increase in distortion in this otherwise "well-engineered powerhouse": "this is not an amplifier suitable for sustained high-power use." (Vol.38 No.6 WW)

Jadis Orchestra Reference Mk.II: $4795
The latest version of an integrated amp that has been a Jadis mainstay since the late 1990s, the Orchestra Reference Mk.II uses two Russian-made EL34 pentode tubes per channel to produce its specified 40Wpc; phase inversion and buffering come courtesy of one 12AX7 dual-triode tube per channel, while input gain is provided by bipolar transistors. The line-only, nonbalanced amp has five inputs, and is available with a remote handset for an extra $350. AD described the "beautifully built" Jadis as having "a full but reasonably explicit bottom, a richly colorful midrange, and a sense of grand spatial scale." More to the point, he praised the amp's talent for melodic, dynamic, and temporal nuance, and declared that the Jadis is "extremely unlikely to disappoint the music-loving, tone-loving audiophile" who owns efficient speakers. JA joined AD in grousing that bias adjustments on the semi-impenetrable Jadis are difficult to effect, and raised an eyebrow at the amp's not-unexpected higher distortion into loads of relatively low impedance—but noted, "the Jadis Orchestra performed well . . . given its circuit topology." (Vol.38 No.12 WWW)

Naim Nait 2/AVO Ultimate Upgrade: $2190 plus cost of Nait 2 $$$
In 1988, the quasi-complementary, class-AB Nait 2—a revised version of Naim's budget-priced, entry-level Nait—distinguished itself as an exceedingly fine-sounding integrated amplifier and one of the stars of Naim's product line. Fast-forward to 2016, when vintage examples of the Nait 2, no longer in production, continue to win raves from budget-conscious audiophiles—although by now most Nait 2s require servicing. Enter AV Options, which employs ex-Naim staffers and offers various levels of service and rebuilds. Their Ultimate Upgrade for the Nait 2 ($2190) involves replacing and recalibrating 14 transistors (including the output devices) and scores of passive parts (including jacks and sockets), plus deep-cryo treatment of the original transformer and other components. AD loved listening to the AVO-upgraded Nait 2, praising its "profoundly excellent sense of momentum and timing" and offering special praise for its great-sounding MM phono section. Bonus points for being able not only to drive Quad ESLs but to make them sing. (Vol.39 No.5 WWW)

Naim NAIT 5si: $1995
Introduced 30 years after Naim Audio's original Nait, the new Nait 5si is a 60Wpc (into 8 ohms) integrated amp with a built-in headphone amp, and with inputs for four line-level sources—but no phono preamp. Inputs are selected with soft-touch buttons, and all are addressed with RCA plugs, while two of those are also equipped with DIN inputs: Naim's traditional preference. HR enjoyed the Nait 5si for tracking complex rhythms with perfection, and for keeping even the most microscopic pitch intervals "in good focus." The Nait 5si lacked color and spaciousness compared to HR's more expensive tubed integrated, but "made it easy to hear—watch—[the music's] rhythms. Forward momentum was spellbinding: The Nait directed my attention toward how the players attacked their instruments." Apart from inverted signal polarity on the headphone output, JA found nothing untoward in his measurements—noting, in fact, that the Nait developed more output power than specified. HR summed up: "The Nait 5si is a world-class integrated amplifier that delivers more audio precision and musical enjoyment than any self-respecting anti-imperialist should ever need." (Vol.37 No.10 WWW)

Octave Audio V 40 SE: $4500
The entry-level V40 SE Line, from Germany's Octave Audio, is an integrated amplifier with an active line-only preamp section and—despite its model designation—a push-pull output section, using two KT88 pentode tubes per side to produce 40Wpc. (A wide variety of similar pentodes can be used instead, but not all will produce the same amount of power.) The output tubes are operated as true pentodes, and the design entails 10dB of global feedback; output-tube bias is user-adjustable via system of which AD remarked, "I have never encountered a surer, safer, less ambiguous, or altogether better means of checking and adjusting tube bias." He was similarly impressed by the Octave's musical performance, describing its ability to portray musical timing and momentum as "superb." AD also enjoyed the V40 SE's "up-front" sound and "better-than-average sense of scale," also noting that while it didn't sound bright, it had sufficiently extended trebles that "reasonable care should be taken in the setup and adjusting of partnering gear." An easy-to-install power-supply enhancement, the Octave Black Box ($1200), made an audible improvement, but shouldn't be considered mandatory. JA noted that the V40 SE "measured as I would expect from a traditional design that uses a pair of KT88 output tubes for each channel," and praised the amp's "impressively high standard" of construction. (Vol.37 No.8 WWW)

Rogers High Fidelity EHF-100 Mk.2: $8000 ★
Made in the US by former NASA engineer Roger Gibboni, the EHF-100 is rated to deliver 65Wpc (JA measured 35Wpc) into 8 ohms; offers four pairs of line-level inputs; and uses two EF86 miniature pentode, two 12AX7 triode, and four KT88 power tubes. Fit and finish were excellent. Though not as nuanced, colorful, or dramatic as AD's reference Shindo separates, the EHF-100 distinguished itself as a tight, punchy-sounding amplifier with loads of natural detail, a very good sense of momentum, and an excellent sense of space. Despite differences in the noise floor between its two channels, the EHF-100 measured well "for a classic design," said JA. Mk.2 has a remote control but is otherwise identical to that reviewed. (Vol.35 No.11 WWW)

Rogue Audio Sphinx: $1395 $$$
The Sphinx is that rarity in contemporary audio: a US-made integrated amplifier with a tubed (12AU7) line stage, a MM-appropriate phono stage, and a headphone jack, all for less than the price of a round-trip ticket to Paris—and Rogue Audio doesn't even make you buy their remote handset ($100). Using Bruno Putzeys's Hypex class-D power modules in tandem with a nonswitching power supply, this hybrid integrated delivers 100Wpc into 8 ohms or 200Wpc into 4 ohms. HR enjoyed his time with the Sphinx, noting its "greater scale and bass force" than his Creek 4330 integrated, and praising its line stage as perhaps "the best of [its] many good features: Everything I played was enjoyably detailed, transparent, and spacious." HR's verdict: "Judging by my experiences with the Sphinx, Rogue's owner and designer, Mark O'Brien, has taken this stigmatized, lower-class mode of operation to a new, more refined level." According to JA, apart from a bit of ultrasonic noise in its output, the Sphinx's amplifier section avoided most of the usual class-D pitfalls, and he particularly praised the MM phono section. 2017 version has upgraded components. (Vol.37 No.8 WWW)

Roksan Kandy K2 BT: $1900
This solid-state integrated amp, descended from the original Roksan Kandy K2 (reviewed by AD in Vol.33 No.5), is notable for offering both an MM phono stage and a Bluetooth input alongside its three line-level inputs. The Kandy K2 BT, which also provides a pair of preamp-out jacks and a bypass input for AV fans, delivers 140Wpc into 8 ohms and 250Wpc into 4 ohms. In HR's system, "The K2 BT showed consistently good tone and scale, but music often felt a tad soft and round—especially at the edges of string plucks and keystrokes." That said, HR declared that "[the Roksan's] phono stage was the best I've heard in a moderately priced integrated—it played LPs in living color." As for Bluetooth, HR was underwhelmed, noting that "the detail, life and naturalness exceeded my expectations but I was disappointed by the amount of low-level fuzz and blur I was noticing." He found that Bluetooth music sounded best when playback levels were kept in check. In his measurements, JA echoed that last sentiment—"if you use the Roksan's BT input, keep your source's volume control down"—and commented that the K2 BT's frequency response "depends to a larger extent than usual on its volume-control setting." (Vol.37 No.11 WWW)

Schiit Ragnarok: $1699
Referred to by its manufacturer as "an intelligent amplifier for headphones and loudspeakers," the Ragnarok—Old Norse for "fate of the gods"—is a solid-state integrated that offers 60Wpc into 8 ohms, 100Wpc into 4 ohms, and no LED display, menu, or remote control. For those omissions, HR thanked the gods. He also praised the "uniquely rich and boldly forceful" sound of the Ragnarok when used to drive the Technics SB-C700 speakers, and declared the "cheerful, articulate" pairing of Ragnarok and KEF LS50s "the most enjoyable stereo system I've used in the 21st century." (HR's second-most-enjoyable pairing: the Schiit Ragnarok with Magnepan .7 speakers, which like power the way Shane MacGowan likes beer.) While measuring the Ragnarok, JA discovered that, when amplifying continuous test signals at high levels, the amp's THD+N rose to as high as 34%. Schiit explained that this "expected" behavior was due to the amp's microprocessor-based bias-management system, which mistook the un-music-like tones for runaway bias. JA altered his testing regimen to account for this departure from the norm and came up with better-looking numbers, but his eyebrows remained somewhat elevated. (Vol.39 No.5 WWW)

Unison Research Unico Primo: $2550
The entry-level integrated from Italian manufacturer Unison Research, well known for their more radically styled power amps, the Unico Primo mates a tubed front end (one ECC83/12AX7) with an 80Wpc solid-state output section running in what Unison calls "Dynamic class-A." An optional plug-in board, also solid-state, provides MM/MC phono capabilities. (The Unico Primo is available without phono for $2400.) In addition to boasting what KM described as a volume control with "the creamiest action I've ever laid fingers on," the Unico Primo "charged hard 24/7, with enough dynamic gusto to compel music mightily." KM added that the slightly warmish Unison Research amp "struck an unusual balance between superior resolution in the treble to midrange and weighty low-end fundamentals that were less than accurate." Reporting from the test bench, JA noted a bit more distortion and noise than desired, but very good phono-stage performance. Optional black faceplate adds $150. (Vol.39 No.7 WWW)

C

Music Hall a15.3: $549
Rated at 50Wpc into 8 ohms or 75Wpc into 4 ohms, the Music Hall a15.3 is a full-size (16.9" W by 3.1" H by 13.2" D) integrated amplifier that includes a MM phono input, mini-jack and RCA line-level inputs, and a front-panel headphone jack. SM admired the a15.3's "high level of fit and finish," adding that the amp performed without flaw in his system. Using the a15.3 with Music Hall's companion c15.3 CD player–DAC and comparing it with NAD's C 515BEE CD player and C 316BEE integrated amplifier, SM found that the a15.3 sounded "more open and airy, and produced a wider, deeper soundstage with beautifully focused images," although it "lacked the NADs' intangible smoothness and musical flow." Among the inputs offered, none impressed SM more than the a15.3's phono stage, which "sounded superb—quiet, dynamic, and emotionally compelling." (Vol.37 No.6 WWW)

NAD D 3020: $499 $$$ ★
Launched to celebrate NAD's 40th anniversary, the 30Wpc D 3020 takes only its name from the company's iconic 3020 integrated amplifier; every other aspect of the design has been thoroughly modernized. It uses a switch-mode power supply, lacks a phono stage, and has only a single analog input, but includes a front-panel headphone minijack; an optional 6dB bass boost; a subwoofer output; coaxial, optical, and 24-bit/96kHz-capable asynchronous USB inputs; and uses an audio-optimized aptX codec for Bluetooth streaming. Weighing just 3 lbs and measuring an unusual 73/8" H by 25/16" W by 85/8" D, the D 3020 can be placed horizontally, like a traditional component, or stood upright, like a modem or hard drive. Uncommonly sensual for a hi-fi product, it has a large, textured volume knob; soft, smooth side panels; and a touchscreen that occupies its entire front panel and extends through one entire side panel. The sound from every input was warm, present, and naturally detailed; even low-quality MP3s streamed wirelessly via Bluetooth were engaging, said SM. "Right now, NAD's D 3020 is the best bargain in all of hi-fi," added ST. Borderline Class B. (Vol.36 Nos. 11 & 12, Vol.38 No.5 WWW)

PS Audio Sprout: $499 $$$
Designed in Colorado, and built in China, the PS Audio Sprout is a compact (6" W by 1.75" H by 8" D) integrated amplifier with built-in MM phono preamp, 24-bit/192kHz USB D/A converter, and Bluetooth receiver. The Sprout's class-D power amp can deliver up to 33Wpc across an 8-ohm load, and its front panel incorporates a ¼" headphone jack, use of which automatically mutes the loudspeaker output. In his review, HR observed that the Sprout occasionally lent the sound "a trace of darkness—not grayness or lack of color," but he found that the little Sprout consistently "demonstrated an ability to engage my attention and keep it locked on the space, character, and artistry of the music being played." HR also felt that the Sprout's Bluetooth wireless performance was "richer, more detailed, less hollow and vapid than any Bluetooth sound I've tried so far," though he found the Sprout's sound through headphones less rich than through speakers. Apart from a response-curve bump centered at 67Hz, JA's measurements uncovered nothing untoward. HR's conclusion: "The Sprout specialized in the beguiling reproduction of every kind of music I sent through its four inputs." The price dropped from $799 to $499 in September 2015. (Vol.38 No.5 WWW)

Editor's Note: There are no Class D intregrated amplifiers listed.

Deletions
Ayre Acoustics AX-7e, Jadis I-35, Kondo Overture, Lepai LP7498E, LFD NCSE, PrimaLuna DiaLogue Premium, Unison Research Simply Italy, all not auditioned in a long time.

Complete Audio Systems

A

Eclipse TD-M1: $999
The TD-M1 system comprises a pair of desktop loudspeakers, each of which has a single 3" full-range driver in a reflex-loaded and vaguely egg-shaped enclosure, the latter made with an alloy frame and a molded exoskeleton. Of each TD-M1 pair, one enclosure also contains a 20Wpc digital amplifier and a 24-bit/192kHz USB D/A converter, the latter equipped for wireless streaming via Apple AirPlay. Aside from grousing about high-tech user controls that were slightly too obscure, AD had fun with the easy-to-install TD-M1 system, enjoying in particular its very accessible WiFi function. All in all, AD's time with the Eclipse system left him giddy: "I had a great time with this system whenever I used it—and it was always easy." (Vol.38 No.5 WWW)

B

Bluesound Vault, Powernode, Node, Pulse, Duo: $449–$999
Bluesound is a new line of whole-house sound products from the Lenbrook Group, owners of NAD and PSB. The Bluesound Vault ($999), which requires an Ethernet connection to the Internet, is an 11.5" W by 9.3" H by 8.1" D box containing an optical drive, a 24-bit/192kHz Cirrus-Logic sigma-delta DAC, and 1TB of storage. Inputs are Ethernet, WiFi, USB Type A, and, by means of an optional dongle, Bluetooth. Outputs include an analog RCA pair and digital TosLink capable of passing up to 24/192 data to an external DAC. The Bluesound Powernode ($699), which looks identical to the Vault but is slightly smaller, is a network player with a 24/192 DAC. The Powernode has the same complement of inputs as the Vault, while its outputs are a subwoofer-out jack (RCA) and two pairs of binding posts for speakers. The Powernode can operate with or without the Vault; in the latter case, the Powernode will access music files from the user's NAS. The Bluesound Node ($449) is—get ready for it—rather like the Powernode, but without (output) power. The Bluestone Duo ($899) is, in the words of ML, "a straightforward satellite-and-(self-powered)-subwoofer loudspeaker system designed by Paul Barton of PSB Speakers [and] meant to be powered by the Powernode." And the Bluesound Pulse ($699) is a 13.4-lb "network-ready boom box" that runs on AC wall current. With Bluesound products scattered throughout his home and with the system as a whole accessing files on his QNAP NAS, ML found the sound of the Bluesound "ecology" to be pleasantly rich and full, if, in some instances, a bit dark; with regard to the latter quality, inclusion of the Auralic Vega DAC restored the missing sparkle. "I enjoyed my time with the Bluesound components," ML stated, noting that the Pulse was perhaps the pleasantest surprise of the lot. Current v2 versions are cosmetically different from those reviewed but otherwise identical. (Vol.37 No.7 WWW)