Recommended Components

A:

ampsandsound Bigger Ben: $5600
This single-input, single-ended, triode-wired, no-negative-feedback tube amplifier drives both loudspeakers and headphones. It offers approximately 8Wpc into 8 ohms and 5Wpc into 32 ohms (when equipped with a solid state rectifier and KT88 output tubes). With 6L6GC output tubes, when it maxes out at 3Wpc, the Bigger Ben powered Zu Soul Supreme speakers "to greater levels of transient and timbral exactitude...than most any other amp I've tried," wrote HR. With DeVore Orangutan O/93s, HR found the Ben every bit as natural and engaging as the First Watt F8 and Elekit TU-8600. Driving HiFiMan's hard-to-drive Susvara headphones, HR described the Bigger Ben as having a radiant quality—"as if the sound were illuminated from within." Rated A+ as a headphone amp. (Vol.44 No.4 WWW)

Anthem STR Integrated: $4999.99 ★ $$$
Anthem's solid state STR integrated amp offers 200Wpc (into 8 ohms) of class-AB power, along with seven analog inputs—one balanced, four single-ended, and two phono (one MM, one MC). It also offers a 32-bit/192kHz D/A processor with six digital inputs—four S/PDIF (two RCA, two TosLink), one AES/EBU (XLR), and one USB. A subwoofer output is provided, but, curiously, there's no headphone output. Of interest to users with problematic listening rooms is the STR's built-in Anthem Room Correction (ARC) processor: using the supplied microphone, ARC can be set up using a PC that's been configured with the appropriate (downloadable) software and connected to the Anthem's miniUSB or Ethernet jack. (The latter has no other function: the STR is not Wi-Fi capable.) Even before setting up and trying ARC, TJN enjoyed the Anthem STR for sounding, with one recording in particular, "punchy and likely true to the source, with excellent detail and an open midrange." With ARC engaged, TJN heard differences that "ranged from subtle to striking...and were only rarely inconsequential." Benefits included a "cleaned up" double-bass sound on one CD, greater upper-bass precision in the sounds of massed voices on another. His conclusion: "a watershed product worth serious consideration." Writing of his experiences in measuring the Anthem STR, JA called it "a well-engineered amplifier offering high powers and respectable measured performance." (Vol.41 No.7 WWW)

Audio Note Meishu Phono 300B Tonmeister (Standard version): $15,740
This class-A, zero negative feedback, single-ended-triode integrated's power supply uses a 5U4G tube rectifier, with each channel's line input using a Psvane Hifi Series 12AU7/ECC82 and a NOS Philips ECG 5687WB to drive an interstage transformer. Each phono input channel uses a Psvane Hifi Series 12AX7/ECC83 and either a Sovtek/Electro Harmonix 6922 or a Russian ECC88. A single Psvane Standard Hifi Series 300B tube provides the output power, specified as 8Wpc into 8 or 4 ohms from the appropriate transformer tap. KM found this plenty enough power for his high-sensitivity DeVore Fidelity O/96 speakers. Playing LPs, he wrote that the Audio Note's performance "was whole cloth, transparent, with superquiet, black backgrounds. It was texturally and tonally beautiful. Mesmerizing, providing new insight into familiar recordings, resolving previously unheard details." "Words fail to express the satisfaction I derived listening to music through this expensive Audio Note integrated amplifier," KM concluded. In the test lab, JA concluded that the Meishu Phono Tonmeister's measured performance was what he would expect from an amplifier with a single-ended output stage that uses a single 300B tube for each channel. It featured a high source impedance and high levels of predominantly second-harmonic distortion, even at low powers. While noting the measured performance characteristic of its type, Editor JA2 awards Class A for exceptional musicality. (Vol.46 No.2 WWW)

Audio Research I/50: $5500
This tidy-looking all-tube amplifier uses two matched pairs of 6550WE output tubes and three 6922 small-signal tubes. There are balanced and single-ended line inputs, a headphone output, and 4 and 8 ohm speaker outputs. Two optional modules are available: a DAC ($1000) and an MM phono ($750)—these were not fitted to JA's review sample. JA was impressed by the ergonomically friendly control offered by both the remote and the top panel buttons and knobs: the I/50 "is a combination of classic tube amplifier design with 21st century microprocessor-controlled functionality," he wrote. Even though neither speaker is a particularly demanding load, JA found that the 4 ohm outputs worked best with his KEF and GoldenEar minimonitors, the amplifier's midrange smooth- and natural-sounding. With the 8 ohm outputs the balance was somewhat forward-sounding with a touch of glare in the midrange, he noted. The balanced input's gain was 6dB lower than the unbalanced, which might mean that the Audio Research may not play loud enough in a room larger than his or with insensitive loudspeakers, unless used with a single-ended source. In JA's test lab, the I/50 met its specified maximum power of 50Wpc from the 8 ohm tap into 8 ohms at 3% THD+N but was 0.5dB short of the specified figure from the 4 ohm tap. He summed up the Audio Research's measured performance by writing that the amplifier is happiest when it is driving a higher impedance than the nominal values of the output transformer taps. "While the distortion signature is primary the subjectively benign second harmonic, the I/50 offers better linearity from its 4 ohm tap," he wrote, concluding that the I/50 has a touch of that "tube magic," "but without going whole hog, as so many of the current crop of tubed amplifiers do." (Vol.46 No.9 WWW)

AVM Ovation A 6.2 ME: $9995
Full-featured, German-made integrated includes balanced and single-ended inputs, all with adjustable sensitivity, a high-resolution "digital" volume control, tone controls, and a discrete headphone output. Runs hot due to the MOSFET output stage being heavily biased into partial class-A operation. HR felt that the A 6.2 ME "imparted a sense of polish, or 'wetness'" to the "almost-dry-but-not-dry sound" of the Falcon "Gold Badge" LS3/5a's. Compared with his long-term reference, the Rogue Sphinx V3, HR commented that the AVM "lit up the music, making it brighter, more vivacious, more right there in front of me, more pacey, and—I think—more meaningful." AVM specifies the A 6.2 ME's maximum output power as 180Wpc into 8 ohms and 300Wpc into 4 ohms. With both channels driven the Ovation delivered 190Wpc into 8 ohms and 315Wpc into 4 ohms. HR liked the sound of the headphone amplifier with sensitive headphones but found that it struggled to deliver undistorted power into the HiFiMan Susvara's difficult load. JA's measurements confirmed that the headphone output clipped at a relatively low voltage, but he wondered if this problem was specific to the review sample. (Vol.44 No.6 WWW)

Ayre Acoustics EX-8 2.0 Integrated Hub: $8000—$11,100
JA reviewed the original version of this integrated amplifier, which had an onboard D/A processor and a Roon-Ready Ethernet port, in the February and April 2019 issues of Stereophile. The 2.0 version's 100Wpc output section still features Ayre's feedback-free Diamond circuit, but it doubles the number of output devices, allowing it to drive more difficult loads and increasing its power output into 2 and 4 ohm loads. (JA measured clipping powers of 107Wpc into 8 ohms and the specified 170Wpc into 4 ohms, compared with the original EX-8's 125Wpc into this load.) Listening to LPs with an external Tavish phono preamp feeding the Ayre's line inputs, KM wrote that the EX-8 2.0 is "one sweet honey of an integrated amplifier...Its outstanding sonic trait is its focused, pristine clarity, a gently scrubbed vision that frames music with refinement, richness, and lucidity." Turning to digital, he wrote that "the trademark Ayre sweetness imbued deep organ notes and electric bass with lushness. An upper-midrange-to-treble crispness aided vocals and guitars, with excellent sustain." He did note that the EX-8 2.0 had a "first row" perspective but concluded that "with its pure treble, clear and rich midrange, ample low end, and coherence, the Ayre is the finest solid state integrated I've had in my house." Analog-only price is $6450; S/PDIF and AES3 inputs add $1000; USB input adds another $500; Ethernet port adds $1700 to base price; fully loaded version costs $8350. (Original version, Vol.42 Nos.2 & 4, WWW; 2.0 version, Vol.44 Nos.11 & 12; Vol.46 No.1 WWW)

Boulder 866: $15,500; with streaming DAC $17,000
This beautiful-looking, made-in-America, powerful integrated amplifier features a class-AB output stage that is heavily biased into partial class-A operation. As a result, it runs very hot and needs to be given adequate ventilation. Analog inputs are all balanced; the optional digital-input module adds Ethernet, USB, AES3, optical S/PDIF, and Wi-Fi. JVS was impressed by the 866's analog inputs. While the 866 couldn't produce a soundstage as wide as his big monoblocks do, its bass wasn't as firm as that of more powerful, more expensive amplifiers, and it couldn't deliver ultimate transparency, "the music's essential color palette, and its message, were as captivating as they are with any equipment...I felt I could trust the Boulder 866 to be there for me, time after time, delivering sonic truth." Playing music with the Boulder's Ethernet input and Roon, JVS felt that the 866 sounded far better than he expected a $1500 DAC to sound, with a wider soundstage than he was anticipating. He concluded that "the quality of its optional DAC blew me away." Measured performance with the analog inputs was superb, with excellent channel separation, very low noise, and low, predominantly third-harmonic distortion. With both channels driven, the 866 exceeded its specified maximum power into 8 ohms of 200Wpc, clipping at 1% THD+noise at 210Wpc. As is often the case with integrated amplifiers the 866's digital inputs had too much gain, but offer just above 18 bits' of resolution. Class A rating applies to use with analog inputs only. (Vol.44 No.9 WWW)

CH Precision I1 Universal Integrated Amplifier: $38,000—$53,000 ★
CH Precision's decidedly modular I1 Universal integrated amp—D/A processor can be had with a variety of extra-cost options, including a USB digital-input board, an Ethernet-input streaming board, an MC phono-input board (with more EQ curves than just RIAA), and a clock-synchronization board that permits the use of an outboard digital clock. In its base form ($38,000), the I1 provides one pair each of balanced (XLR) and unbalanced (RCA) analog inputs, plus an S/PDIF digital-input board and two balanced (XLR) stereo outputs. Echoing the future-proof design of the amp itself is the I1's D/A processor, which is coded into a field-programmable gate array (FPGA); this upsamples 16-bit/44.1kHz PCM and its multiples to 24/352, and 16/48 PCM to 24/384. The I1 handles up to DSD2565 and converts all DSD data to 24/352.8 before playback. Its class-AB output section can provide up to 100Wpc into 8 ohms. Notwithstanding some setup complexities, JVS was able to get from the I1 "some mighty impressive sound," and to the extent it fell short of his own (costlier) reference gear, those were "sins of omission rather than of commission." JVS found the CH Precision's sound to be "clean, strong, and direct," yet it did not "filter out those intangibles that allow the music to elicit a powerfully emotional response." His verdict: "one of the most complete, most neutral sounding, most carefully conceived components I've reviewed." Writing from his test bench, JA praised the I1's "excellent measured performance," and in his own auditioning of a sample with updated, Roon Ready firmware, found that 40% overall negative feedback gave the optimal balance between low-frequency definition and the unfatiguing presentation of high- frequency detail. (JVS preferred 0% feedback.) JA was impressed by the DAC performance, writing that imaging was precise, the soundstage deep when appropriate, and the midrange uncolored. "Low-level recorded detail was present in abundance but without the feeling that it was being unnaturally emphasized," he concluded. (Vol.42 No.2, Vol.46 No.8 WWW)

Decware Zen Triode Amplifier: $1195 $$$
Decware 25th Anniversary Zen Triode Amplifier: $2995 without tubes; $3395 with "curated" tubeset
The 2.3Wpc Zen Triode is a class-A, zero-feedback, single-ended stereo tube amplifier that uses just two resistors and one Jupiter Beeswax film capacitor in its signal path. The output tube is a triode-wired, self-biasing, self-balancing 6N15N (equivalent to a 6BQ5/EL84). The voltage amplification tube is a 6H1N/6N1P dual triode (equivalent to a 6922/6DJ8). With the Denafrips Ares II DAC and Klipsch RP-600M loudspeakers, HR noted a "conspicuous purity of sound" resulting in one of his "most thought- and pleasure-filled musical moments of 2020." "With the Zen's bias switch on High," he added, "music from the RP-600Ms was reproduced with a level of overt vividosity that I had not experienced previously." The considerably more expensive 25th Anniversary Zen Triode Amplifier features an African Padauk hardwood plinth, gold-plated switches, super-duty gold-plated tube sockets, NOS Western Electric Milliamp meters, a choice of knobs for the dual-mono volume controls, and three independent, tube-regulated power supplies, one for each tube. "Without 100dB/W/m horns, the Zen Triode will not crush rocks or destroy planets," HR wrote. "But driving the modest Zu Audio Soul Supremes, it will play Mahler's Symphony No.5 as performed by the Berlin Philharmoniker under the baton of Sir Simon Rattle...with dark, moody vigor and delicious, microdetailed insights." (Vol.44 No.3 WWW)

Elekit TU-8900: from $1945 without tubes
HR was impressed by this relatively inexpensive, heavily parts-curated, made-in-Japan, tubed kit amplifier. (It can be purchased preassembled for a $375 premium. A clear top plate is included in this cost, and is a $35 kit option.) Lundahl amorphous-core output transformers are combined with 12BH7A small-signal tubes and 300B or 2A3 output tubes, both wired without cathode feedback but with 8dB of loop negative feedback. (This can be switched out.) Specified output power is 8Wpc with 300Bs, 3.5Wpc with 2A3s, both at 10% THD. The review sample was fitted with the Audio Note Silver upgrade ($960), which adds Audio Note 0.1µF silver-foil coupling capacitors, 46 tantalum signal path resistors, two Amtrans AMRG resistors, and four Takman carbon resistors. The Elekit's four tube-set options begin at $365, for two Cossor/LinLai Delux 2A3s and two Sylvania 12BH7As, and top out at $1525 with a matched pair of Western Electric WE300Bs (with a 5-year warranty) and two US-manufactured Sylvania 12BH7As. After much experimentation using multiple speakers, HR decided that he preferred the TU-8900's presentation without loop negative feedback: "Everything felt more impactful, more emotionally fleshed out. Every Elekit 300B virtue was enhanced, especially texture and transparency." "This kit delivered the nuance, intensity, and dramatic transparency of big-name 300B amplifiers costing many times its price," he wrote. HR was also impressed by the TU-8900's headphone output. Driving low-impedance HiFiMan Audivina closed-backs, he found that the Elekit sounded authoritative, though he felt that it got a bit tense and dulled trying to drive HiFiMan's less-sensitive Susvaras. (Vol.46 No.7 WWW)

European Audio Team E-Glo I: $12,999 and up, depending on tube complement
This elegant-looking integrated amplifier uses a 12AX7 and a 12AT7 signal tube and a pair of KT88 tubes for each channel. There are two output transformer taps, optimized for 4 or 8 ohm loudspeakers. Specified maximum power is 35Wpc into 4—8 ohms in Ultralinear mode or 18Wpc into 4—8 ohms in triode mode, which JA's measurements confirmed, though at a slightly higher level of THD+noise than the Stereophile-standard 1%. With his DeVore O/93 speakers driven from the 8 ohm outputs, KM wrote that the E-Glo I's sound was "vivid, fast, forceful, clean, very open, spacious, transparent, dynamic, resolving, and full-bodied—even full-blooded. It served up good helpings of what Art Dudley called 'drive.'" KM preferred triode mode, finding that while Ultralinear made the sound more immediate and upfront, there was "a smidgen's loss of delicacy." Summing up, he wrote that "In its ability to create a supercharged musical presentation within a large soundstage populated by big images, allied to superb definition and resolution, with good tone, the E.A.T. E-Glo I gets so many things right in such a balanced, forceful presentation that I'd say it's worth its asking price." (Vol.43 No.12 WWW)

Grandinote Shinai: $15,000
Echoing tube-amplifier topologies, the Italian, dual-mono, fully balanced Shinai features two single-ended, class-A, solid state output stages in a push-pull arrangement for each channel, with no loop negative feedback. "As long as I am Grandinote boss," designer Massimiliano Magri told RS, "feedback will be prohibited like sincerity in politics." RS liked what he heard from this unique amplifier: "The Shinai made aural space microscopically tangible," he wrote, adding that the amplifier has "a knack for detail retrieval" and "gave notes and musical lines enough space to stretch out and seamlessly transition into the next notes and musical lines." This transparency was achieved without the presentation sounding clinical or etched: "The Shinai has the spirit of a revealer. It speaks the truth—not ruthlessly, but honestly." In the test lab, the Shinai almost met its specified maximum power of 37Wpc into 8 ohms at 3% THD+N, though JA warned against using the Grandinote with speakers whose impedance dropped below 4 ohms. JA summed up the measured performance by saying that it "is dominated by the designer's decision not to use negative feedback. I would expect the Shinai's sonic character therefore to be similar to that of a typical tube amplifier." However, RS concluded that the Shinai "did some things better than my tube gear—definition, detail, space, scale, touch." Two months after he submitted his review, RS was astonished to find that the Shinai's sound exploded: "It blew open musically. As good as it was already, the sound went from here up to there, overnight." An enigma, but lengthy listening sessions confirmed his impression. He concluded that the Shinai sounded "rich and bloomy but with a sense that you're hearing the true, original thing and not a recording." (Vol.43 No.11, Vol.44 No.4 WWW)

Jadis Orchestra Black: $5795
Derived from the Jadis Orchestra Reference Mk.II integrated amplifier ($4795) that AD reviewed in December 2015, the Orchestra Black is a less-expensive version developed for the US market. It retains the Mk.II's mostly hard-wired circuitry and the fixed bias for each channel's push-pull pair of 6CA7/EL34 power pentodes but uses transistors to provide voltage gain. AD wrote that the Black initially had "that treble lisp that I assume many of you have heard from amps and preamps that aren't yet run in—audible here as an exaggeration of note attacks from violins," but found that as the amplifier broke in, it became considerably more listenable, though still slightly on the dry side. He commented on how the amplifier complemented the sound of the harp: "Each plucked note had pretty good—not top-shelf, but perfectly satisfying—physicality of attack, but even better decays: maybe a slight bit too much overhang, but in a pleasant, musically consonant way." AD was also impressed by the Black's bass: "The lowest notes had plenty of power and reach and a slightly frightening physicality," he wrote, ascribing this to the Jadis's hand-wound output transformers. In his measurements, JA found that the Black had an unusually high output impedance—3.5 ohms—and that it only met its specified power of 40W at higher levels of distortion than our usual 1%. The Jadis should not be partnered with loudspeakers whose impedance drops below 4 ohms, JA concluded. Nevertheless, "very strongly recommended" was how AD summed up his auditioning. (Vol.43 No.4 WWW)

Linear Tube Audio Z10e: $6950
See "Headphones & Headphone Accessories." (Vol.43 No.5 WWW)

Marantz MODEL 30: $2999 $$$
This elegant-looking amplifier's output stage uses Hypex NC500 class-D modules and is specified at 100Wpc into 8 ohms or 200Wpc into 4 ohms. JA's measurements indicated the Model 30 significantly exceeded those powers, clipping at 165Wpc into 8 ohms and 240Wpc into 4 ohms. Not always a fan of class-D amplifiers, HR wrote that "the Marantz version of class-D clarity brought greater transparency to the upper five octaves, in a way I have not previously experienced with any class-D module." Compared with the more expensive Yamaha A-S3200, HR felt that while the Yamaha represented "bright-n-ready, old-school, class-AB vivo," the Marantz sounded darker, less extraverted, with "more silence in the silences and more space in the soundspaces." He also found that the Marantz partnered well with Magnepan .7 speakers, pulling out "shovelsful of previously hidden subtleties." The Model 30's headphone output will work better with high-impedance 'phones. No digital inputs, but the Marantz has a versatile, low-noise, low-distortion phono stage that offers a moving magnet mode and three moving coil modes, labeled MC Low, MC Mid, and MC High, and different combinations of gain and resistive loading. (Marantz also offers a matching SACD player/streaming DAC, the SACD 30n.) HR summed up his auditioning, "The Marantz Model 30 integrated suits my taste for simple sophistication. Its phono stage is...versatile and musically effective...Best of all, this stylish new Marantz is a well-tuned, supertransparent, superdetailed class-D amplifier that powered diverse loudspeakers with a captivating élan worthy of its 'Model 30' heritage." (Vol.44 No.1 WWW)

McIntosh MAC7200: $8000
This classic stereo receiver may well be the most expensive model currently available, but LG was mightily impressed by what it offers. In addition to McIntosh's traditional blue level meters and an excellent FM stage, it offers S/PDIF and USB digital inputs, line and MC/MM phono analog inputs, and a headphone output. (JA's measurements suggest that the latter will work best with high-impedance cans.) The transformer-coupled, solid state output stage offers a maximum power of "at least" 200Wpc into 2, 4, or 8 ohms; JA measured 255Wpc into 8 ohms, 235Wpc into 4 ohms, and 283W into 2 ohms from the respective output-transformer taps. LG found that the MAC7200's tuner equaled his Day Sequerra FM Reference's ability to generate a jet-black background and render broadcast music punchy, dynamic, and involving, although it lacked the FM Reference's transparency and selectable bandwidth filters. "The FM tuner is this product's jewel," he wrote, adding, "its sensitivity, selectivity, and ability to quiet with an FM signal equaled and in many cases bettered my FM Reference tuner." Auditioning the MC phono input, LG noted that it rendered a favorite LP with stunning transients, wide soundstage, and incredible detail, easily besting the CD version of the same work. He also liked what he heard from the Mac's digital inputs, commenting that they matched his reference Bryston DAC's dynamics, background quietness, and depiction of the soundstage. Summing up, LG wrote that the MAC7200's power, resolution, dynamics, and transparency are among the best he has heard: "If you have the sturdy shelf space for its large, heavy chassis, are a fan of FM radio, and are looking for one unit to handle many different two-channel tasks, the MAC7200 should be on your short list." (Vol.44 No.1 WWW)

Moonriver 404 Reference: $5995
As supplied for review, this Swedish amplifier included optional digital and MM/MC phono analog inputs. The digital module, though, was based on an AKM DAC chip that is no longer available following the disastrous fire at the Japanese manufacturer's factory, so the review didn't discuss the digital input. But with the single-ended line inputs, JVS wrote that while the sense of air wasn't as breathtaking as through his expensive reference amplifier, "the music sounded airier and more colorful and seemed to emerge from a quieter background" than what he'd recently heard through the two more expensive integrateds. "Plenty of bass showed that the low-powered Moonriver 404 Reference has what it takes to drive the challenging Wilson Alexia 2's," he added. Summing up, JVS wrote that the Moonriver 404 Reference "does justice to complex and demanding recordings. It sounds tonally spot on, well balanced, clear, and musical." Although the 404 Reference uses an output stage based on Texas Instruments' LM3886 chip, which is specified as being able to deliver 50W into 8 ohms and 70W into 4 ohms, JA found that the Moonriver clipped at 39.5Wpc into 8 ohms and 60W into 4 ohms. Although the Moonriver has single-ended preamplifier outputs, JVS found that these "buzzed" with his reference monoblocks, and JA found that there was a high level of ultrasonic noise on the preamplifier outputs. (This may have been a sample fault.) In his measurements, JA also noted low-level power-supply spuriae and that the distortion signature was primarily the subjectively benign second harmonic. Intermodulation distortion was not excessive. (Vol.44 No.2 WWW)

NAD Masters Series M33: $4999
This extraordinarily versatile amplifier incorporates a fully integrated BluOS streaming platform, sophisticated control options, Dirac room correction, analog line and MM/MC phono inputs, digital inputs, a headphone output, and an output stage based on the Purifi Eigentakt class-D technology developed by Bruno Putzeys. KR was impressed. Listening to a brass band recording, he found the M33's sound notably transparent. "There was a satisfying balance between the drum and tuba at the low end, the brashness of the upper brass, and the filigree of winds in between," he wrote, going on to say that "the soundstage was full and wide, and there was the impression of significant weight and body." "The M33, in one well-integrated and handsome box, replaces all the traditional components and can be operated from a smartphone or a tablet," concluded KR, adding "Keep your beloved speakers and let the NAD M33 do everything else. It will do it all superbly." On the test bench the M33 exceeded its specified continuous output power of 210Wpc into 8 ohms and delivered 460Wpc into 4 ohms. JA was impressed by the "excellent" phono stage and concluded that "NAD's M33 packs a lot of well-engineered performance into its relatively small chassis." The M33 was both Stereophile's Amplification Component of 2020 and the magazine's overall Product of 2020. (Vol.43 No.10 WWW)

Pass Laboratories INT-25: $7600 ★ $$$
To HR, who prefers integrateds over separates yet wouldn't even consider buying an amp with a built-in DAC—"Why would I pollute a fine audio component with a non-upgradable and possibly third-rate ancillary?"—the Pass INT-25 emerged as an ideal component. The remarkably heavy (51lb) INT-25 is essentially a Pass XA25 power amp—class-A push-pull without degenerative feedback and offering 25Wpc—wedded to a minimalist line-level preamp. Used with his DeVore O/93 speakers and playing Erich Leinsdorf's recording of Wagner's Die Walküre, Herb found that "the INT-25 let the O/93s make that Die Walküre into something so beautiful I just laid back and basked in it." He also felt the INT-25 is capable of putting across "a subtle radiance" that eludes other solid state electronics. With the amp on his test bench, JA found "much to admire in the Pass Labs INT-25's measured performance." HR's last word: "my new solid state reference." (Vol.43 No.2, Vol.46 No.2 WWW)

Riviera Audio Laboratories Levante: $21,995
This hybrid, analog-input–only, Italian design features tubed front-end circuitry and a MOSFET output stage that can be operated in class-A, in which it offers a maximum power of 30Wpc into 8 ohms, or class-AB, in which it offers 120Wpc into 8 ohms. (JA had to relax our definition of clipping to 3% THD+noise for the Levante to meet its specified powers.) There is no global loop negative feedback because the designer believes this causes the distortion signature to mimic that of human hearing. JA found that distortion at moderate powers was close to 0.5%, though this was almost entirely the subjectively innocuous second harmonic. HR's first impression was that the Levante, fitted with vintage Mullard input tubes, sounded "Too lush. Too big. Too densely atmospheric." The review sample was supplied with modern JJ tubes as well as the Mullards. Changing to the stock JJ tubes produced a sound that was more overtly direct, less misty and possessed of a more sharply focused, less-granular clarity than with the Mullards. Other than the increase in power, HR didn't notice much difference between class-A and class-AB operation. The Levante's headphone output had a moderately low source impedance of 18 ohms. While HR found the low-sensitivity, 60 ohm HiFiMan Susvaras sounded slightly rounded off, the sound with the sensitive, 300 ohm ZMF Vérité closed-backs was "unusually precise and vibrant." "I never imagined there'd be an integrated amplifier with a headphone amplifier of this caliber," he concluded. (Vol.45 No.2 WWW)

Roksan Attessa Streaming Amplifier: $3399
This British class-AB amplifier incorporates line and MM phono analog inputs, coaxial and optical S/PDIF digital inputs, and will also decode audio data via Bluetooth, USB, and Ethernet. (It will decode MQA data with the last two inputs.) Roon recognized the amplifier as an AirPlay device, but at the time of JA's review, the Attessa had not yet been certified by Roon. However, after being set up with the MaestroUnite app, it could play audio streamed with BluOS. JA used the Roksan with Mission 770 and GoldenEar BRX speakers and noted that the amplifier kept tight control over both speakers' woofers. He compared the Attessa's S/PDIF inputs with the same data fed to the Ethernet port with BluOS and decided that there was a better sense of palpability and greater subjective low-frequency extension with network data. Using both loudspeakers and headphones, JA noted natural-sounding midrange and highs and an excellent sense of drive in the bass. On the test bench, the Attessa met its specified powers of 80Wpc into 8 ohms and 130Wpc into 4 ohms, with very low distortion at lower powers. The onboard DAC offered around 18 bits of resolution. The phono stage also measured well, with low noise, superbly high overload margins, and accurate RIAA EQ. (Vol.45 No.12 WWW)

Rotel Diamond Series RA-6000: $4499
Solid state, class-AB amplifier with balanced and unbalanced line analog inputs, an MM phono input, coaxial and TosLink S/PDIF digital inputs, and Bluetooth, USB, and Ethernet connectivity. Specified power is 200Wpc into 8 ohms and 350Wpc into 4 ohms, both confirmed by JA's measurements. DAC chip is a Texas Instruments PCM5242, which decodes PCM data up to 24/192 but not DSD data. Playing CDs with Rotel's DT-6000, HR felt that the Rotel excelled at the volume, force, and time-passage parts but fell a breath short on recovering a full harmonic spectrum of tone. With LPs, however, the RA-6000 let recordings sound like themselves, open and clear with no issues to distract listeners. "It was a joy," he wrote, adding that in his system, "the RA-6000 played LPs even better than CDs—and that's saying a lot." The Rotel's own digital inputs sounded much dryer and pared down compared with the DT-6000. "On stringed instruments," HR wrote, "the beauties of texture and harmonics were presented less richly. Nevertheless, performances moved along and presented themselves in a bright, lively way that kept me listening contentedly." On the test bench, the Rotel offered low noise and distortion and high power, though JA noted that the headphone output's very high source impedance won't be optimal for low-impedance headphones. The D/A section had limited resolution, between 17 and 18 bits, and while the phono stage measured well, he conjectured that its rising ultrasonic output might slightly emphasize the audibility of record clicks. (Vol.46 No.2 WWW)

T+A PA 3100 HV: $24,800
This powerful solid state integrated amplifier offers up to 300Wpc into 8 ohms and 500Wpc into 4 ohms—JA measured clipping powers of 318Wpc/8 ohms and 525Wpc/4 ohms. JA also noted that while distortion was not especially low—though it remained below 0.1% at high powers into loads >2 ohms—it was commendably consistent with frequency and consisted primarily of the subjectively innocuous second harmonic. The PA 3100 HV has both balanced and unbalanced inputs and preamplifier and headphone outputs—the latter best suited for high-impedance headphones—as well as the usual loudspeaker outputs. The review sample was not fitted with the optional Tone Control/Room Correction ($2900) or MM/MC phono input ($1600) modules, nor was it supplied with T+A's PS 3000 external power supply ($14,500). Nevertheless, JVS found that this amplifier's "consistently musical presentation" emphasized "smoothness and ease over strong contrasts and abrupt shifts" and described it as "a powerful transmitter of musical truth." He summed up the PA 3100 HV as "an excellent, meticulously engineered, beautifully made integrated amplifier." (Vol.44 No.4 WWW)

Technics SU-R1000: $9999.95, available in black or silver
This groundbreaking "digital" amplifier offers MM and MC phono, line-level, and digital inputs and maximum powers of 150Wpc into 8 ohms and 300Wpc into 4 ohms. (JA's measurements indicated slightly higher clipping powers into both loads.) The SU-R1000 makes extensive use of DSP: "JENO" (Jitter Elimination and Noise-shaping Optimization) eliminates jitter during the conversion of all signal to high–sample-rate PWM to drive the output transistors; "Load Adaptive Phase Calibration" measures the output gain and impedance phase characteristics of the amplifier and speaker to create an ideal impulse response; "Active Distortion Cancellation Technology" compensates for the back electromotive force produced by speakers; and "Intelligent Phono EQ," which optimizes the RIAA equalization and channel separation. (A test LP is included to allow this last feature to be implemented for the user's specific phono cartridge. JA found that even without the Intelligent Phono EQ, the SU-R1000's RIAA correction was extraordinarily accurate—one of the best he has ever measured.) "The Technics SU-R1000 is not a class-D amp 'on steroids,' and it's not a solid state amp emulating a tube amp," wrote KM. "It's unlike any amplifier I've heard. The SU-R1000 achieved levels of performance and sound quality I've not previously heard from any amplifier, except in terms of tone and texture." (KM preferred his reference tube amplifiers for these qualities.) "The SU-R1000 may be technically complex, but its sound was simple, whole, and true with exceptional transparency, flow, and imaging...warm and a touch rich," he decided. JA concluded that the Technics SU-R1000 line-level analog inputs, phono inputs, and digital inputs all offered excellent measured performance. (Vol.44 No.12, Vol.45 No.1 WWW)

Thöress EHT MKII: $10,995
See Herb Reichert's review in this issue's Gramophone Dreams column. (Vol.46 No.10 WWW)

Yamaha A-S3200: $7999.95
The styling of this well-finished, hot-running integrated amplifier evokes memories of the Japanese company's "Natural Sound" receivers from the 1970s. The A-S3200 offers both balanced and singled-ended line inputs, headphone, preamplifier, and loudspeaker outputs, and tone controls. JVS liked the headphone outputs, commenting that "the welcome smoothness and beauty of the presentation, and...the excellent left-right soundstaging, earn the headphone amp a big thumbs up." However, he was less happy with the A-S3200 driving his Wilson Alexia 2 loudspeakers, writing that while "air and depth were pretty good, the soundstage was as wide as I've come to expect from other integrated amplifiers I've evaluated, and musicality was a constant," what stood out most was "a predominant midrange whose color palette, compared to my reference, seemed somewhat restricted." JVS suspected that the Yamaha was not an optimal match for his current-hungry Wilson speakers, mandating a Follow-Up with higher-impedance loudspeakers. In that Follow-Up, HR found that the A-S3200 played more dramatically into Harbeth 30.2 speakers than his reference Pass Labs INT-25 had. "Bass had more force and bite," he wrote and concluded that "this luminous, retro-looking integrated is more than a babyboomer nostalgia toy. It is a serious, high-value music-playing machine." On the test bench, the A-S3200 exceeded its specified maximum continuous power of 100Wpc into 8 ohms and 150Wpc into 4 ohms, clipping at 110Wpc and 168Wpc, respectively. Line-input gain was on the high side, though the MM- and MC-capable phono input offered appropriate gains for both types of cartridge. (Low-output MC types will probably better match this input.) RIAA equalization featured slight boosts in the treble and midbass regions; the phono input's distortion and noise were very low. HR's Follow-Up included an audition of the A-S3200's phono stage. Using a Koetsu cartridge loaded at 50 ohms, the Yamaha "played instruments with exceptionally tight bass and a detail-packed midrange." HR concluded that "Overall, the Yamaha's phono stage far exceeded my expectations," though he warned that those who utilize the A-S3200's phono stage will need to choose MC cartridges with care. Even so, he added that he was certain that no one would be disappointed with the moving magnet input. (Vol.43 Nos.9 & 11 WWW)

B:

AVM Inspiration CS 2.3: $6995
A small integrated amplifier with class-D output stages that integrates a CD drive, offers Ethernet, Wi-Fi, and Bluetooth connectivity and has coaxial S/PDIF, HDMI, and USB-A digital inputs two sets of single-ended, line-level analog inputs and one MM/MC phono with loading plugs. (The analog inputs are not converted to digital.) There are outputs are two TosLink digital outputs; analog preamplifier and subwoofer outputs; a headphone jack, and a pair of small binding posts for loudspeakers. Control can be with the front panel control buttons or AVM's iOS and Android RC X apps. SM found the app intuitive and a pleasure to use. "Navigating menus and submenus felt logical and appropriate." He concluded that while the CS2.3 is not inexpensive, "when you price out everything it does—DAC, streamer, CD player, line and phono preamp, amplifier, headphone amp—and how well it does it, the smallness of that number starts to impress." In the test lab, JA found that the AVM met its specified power of 140Wpc into 4 ohms, the CD transport featured superb error correction, the DAC offered high resolution and a choice of reconstruction filters, and the phono input had superbly accurate RIAA correction and low noise and distortion. He did comment, however, that the amplifier will probably work best with speakers that have an impedance greater than 4 ohms. (Vol.46 No.6 WWW)

Bryston B135³: $6995 as reviewed
The only integrated amplifier Bryston makes, the B135³ combines their BP-17³ preamplifier and 2.5B³ amplifier in one box, available in 17" or 19" versions. An optional DAC card adds $750 to the base price. For another $1000, the Aux 1 input becomes a moving magnet phono input. Writing about the basic amplifier, HR concluded that it "sounds like it looks: understated, recording-studio quiet, detailed, easy-flowing, low-distortion, tone-correct, and low-fatigue. The B135³ always plays music engagingly." The Bryston is specified as offering maximum powers of 135Wpc into 8 ohms and 180Wpc into 4 ohms; JA's measurements indicated that it exceeded those powers, clipping at 155Wpc into 8 ohms and 230Wpc into 4 ohms. HR noted that with his low-impedance headphones, the Bryston's headphone output sounded "rolled-off and unsparkly." JA found that the headphone output impedance was a relatively high 71 ohms, which means that the Bryston will be better suited to high-impedance headphones, like Sennheisers. JA wrote that the B135³ offered extremely low levels of distortion, though he advised that "background noise will be at its lowest when the volume control is below the maximum." (Vol.44 No.12 WWW)

Cambridge Audio CXA81: $1299 $$$
The CXA81 is a versatile, solid state integrated amplifier with analog and digital inputs, headphone, preamplifier, and subwoofer outputs, and the usual loudspeaker outputs. JA found that the Cambridge slightly exceeded its rated power of 80Wpc into 8 ohms and 120Wpc into 4 ohms. Using its line inputs, the CXA81 had KM muttering "wow" (several times) at its transparency to the sound of upstream electronics and recordings. Using both Polk and Quad loudspeakers, the amplifier "consistently created a large, atmospheric soundstage with solid images." The Cambridge's digital inputs were consistently satisfying, though not in the class of KM's reference BorderPatrol DAC, which costs 50% more than this DAC-equipped integrated amp. Compared with the more expensive, "fully loaded" Schiit Ragnarok 2, the CXA81 had better top-end air, a slightly wider and deeper soundstage, and a more laid-back presentation; the Schiit amp offered better tone, slightly better drive, and more intimacy. The CXA81 helped KM realize "how much music can be had for such a low price. It knocked me flat with its ability to sound good in so many ways." (Vol.44 No.1 WWW)

Cambridge Audio EVO 150: $2999
The Roon-Ready, "all-in-one" EVO 150 has digital, line, and MM phono inputs, can stream audio via a network or Bluetooth connection, and can unfold MQA-encoded data. It "continues Cambridge's tradition of offering near-cutting-edge products that don't break the bank," RS wrote. He was impressed by what he heard, finding that the Cambridge sounded "fresh-faced and convivial, with a dynamic spring in its step. There was a confident, unforced quality that let the music unfold gracefully," adding that the amplifier maintained its composure at high volume. JA found that the class-D EVO 150 met its specified maximum power into 8 ohms (150Wpc) and delivered 280Wpc into 4 ohms before clipping. "With the exception of the higher-than-expected levels of noise in its headphone output, the Cambridge EVO 150's measured performance reveals excellent audio engineering," JA summed up. RS was equally impressed, concluding that everything about the EVO 150—its ergonomics, features, streaming app, remote, and, most essentially, sound quality—operated at a high standard. (Vol.44 No.10 WWW)

Fezz Audio Silver Luna Prestige: $2995
A push-pull, class-AB1 auto-bias, tubed stereo integrated amplifier using EL34 output tubes that can be operated in tetrode or pentode modes. The input tubes are either 6N2Ps or 12AX7s. AH preferred the 12AX7s, which produced a larger, meatier sound than the 6N2Ps. He also preferred listening in pentode mode, which offered a fuller-bodied and more extended sound. AH's initial impression wasn't positive, as with this high-sensitivity Klipsch La Scalas, the Fezz amp emitted a steady hum. He found that this hum wasn't noticeable playing back music, and ended up finding that the EL34 push-pull circuit produced a well-balanced, punchy, and generally pleasing sound—"these amps tend to be as familiar and comforting as an old flannel shirt." The Silver Luna "sounded like it was putting a slight emphasis on the upper bass, which made its rendering of the electric bass notes sound scary good," he wrote, adding that the Polish amp showed a remarkable affinity for the human voice, "which it reproduced with eerie presence." While AH cautioned that listeners of primarily classical or jazz will probably feel happier with a more pellucid sounding, better-mannered amplifier, he wholeheartedly recommended the Silver Luna for those who subsist on a musical diet heavy on pop, rock, country, reggae, Afropop, metal, or R&B. In the test lab, the Fezz amplifier's measured performance was a mixed bag. The cleanly extended high frequencies and excellent squarewave performance, had to be put against the high source impedance and the relatively high level of second-harmonic distortion, which suggest that the amplifier will sound different with every loudspeaker with which it is paired. And the amplifier only met its specified 35W output power at 10% THD+N, and then only in pentode mode. (Vol.46 No.8 WWW)

HiFi Rose RA180: $6995
JMu fell in love with the appearance of this steampunk-styled, class-D integrated amplifier from Korea when she first saw it at the 2022 AXPONA. She was equally impressed by its sound quality when she installed the RA-180 in her system. It offers a plethora of features—level meters, a phono MC/MM stage, two rows of speaker outputs to allow operation with two pairs of full-range speakers (two channels or four channels), and switchable channel bridging for greater power—and controls for volume, bass, treble, balance, tone control bypass, biamping crossover frequency and high-frequency gain (to drive a supertweeter), and a choice of five phono EQ settings in addition to RIAA. The RA180 can be controlled with its remote or with HiFi Rose's RoseAMPConnect app for Android or iOS. (The RA180 only recognizes 2.4GHz Wi-Fi networks.) Using her reference MBL 120 loudspeakers, JMu noted that images were realistic, natural in scale: "The presentation felt grounded. Textures were tactile." Changing to bridged output mode, the MBLs' presentation seemed less cohesive, however. JMu tried the RA180's biamping function with the three-way, Triangle Antal 40th Anniversary Edition speakers. Listening to Andrew Bird's Inside Problems on vinyl and 24/96 download, JMu noted that regardless of format, "the presentation was smooth, natural, liquid. Bass lines were clean, easy to follow. Recording-venue acoustics cues, such as slight echo on 'Atomized,' were easy to hear—more so than usual." On the test bench, the RA180 with two channels driven in normal mode exceeded its specified power of 200Wpc, clipping at 290Wpc into 8 ohms and 400Wpc into 4 ohms. More power was available in bridged mode, though the amplifier's protection circuitry operated below the actual clipping power. The phono stage was relatively quiet, with accurate RIAA EQ, but the overload margin at the top of the audioband was limited. JMu concluded that "The HiFi Rose RA180 is big on speed, energy, clarity, and detail. You get plenty of power in a single chassis." JA1 notes that while the RA180 is unquestionably cool, some of its features, like the built-in crossover that's intended for use with supertweeters, are of marginal utility in most systems. (Vol.45 No.12 WWW)

HiFi Rose RS520: $3695
The Roon Ready RS520 marries a GaN FET-based class-D amplifier to the large, 12.25" wide front-panel touchscreen featured on the Korean company's streaming D/A processors. It offers a plethora of audio and video streaming functionality, as well as offering optical and coaxial S/PDIF inputs, USB ports for attaching local storage, and WiFi and Bluetooth connectivity. RvB controlled the RS520 with the HiFi Rose smartphone app and with all the speakers with this he used the amplifier found that there was weight, control, authority, clarity, and palpability. "I heard sweet detail up top that didn't become brittle even on borderline sibilant recordings," he wrote, concluding that the HiFi Rose is "a fast, impressively appointed sports car for the price of a Volkswagen Golf. Fahrvergnuügen indeed!" In the test lab, the RS520 offered generally excellent measured performance, offering a clipping power of 275Wpc into 8 ohms and a DAC with a choice of multiple reconstruction filters and between 19 and 20 bits' resolution. However, JA noted that the class-D output stage had a higher level of ultrasonic noise than he usually finds with such designs. (Vol.46 No.7 WWW)

Line Magnetic LM-845IA: $4895
Replacing HR's long-term reference tube amplifier, the LM-518IA, the Chinese LM-845IA weighs a back-breaking 77lb and still uses a single hot-running 845 tube for each channel's output, but has internal component changes and redesigned output transformers, these sourced from Japan. It also uses 12AX7 input tubes, a 5AR4 rectifier, and a pair of triode-operated 6P3P beam tetrodes to drive the grids of what AH described as "those slightly terrifying 845s." The Line Magnetic offers 4, 8, and 16 ohm speaker terminals, three line-level inputs, and a preamplifier input for those wishing to use the LM-845IA as a power amplifier. A nicely machined aluminum remote with volume and mute buttons is included. What AH noticed first in his auditioning were "the hallmarks of a well-designed single-ended triode (SET) amplifier: a bell-like clarity, lots of textural information, and a distinctive three-dimensionality to the sonic images...With the Line Magnetic and the 16 ohm taps, the soundstage was expansive in width, height, and depth, with instruments and voices floating free of and well above my Altec Valencia 846A speakers." The LM-845IA's maximum power is specified as 22W. JA found that with our usual definition of clipping, which is when the output's THD+noise percentage reaches 1%, with both channels driven with a 1kHz signal the LM-845IA's 16 ohm tap clipped at just 2Wpc into 16 ohms, though it did offer the specified 22W from this tap at 3.5% THD+N. Unusually, the Line Magnetic's 16 ohm and 8 ohm output transformer taps worked best with impedances that were lower than the nominal tap value. However, these two taps have sufficiently high output impedances that the LM-845IA's sonic character will be different with every loudspeaker with which it is used. The 4 ohm tap has a lower output impedance, JA noted, but this is at the expense of higher distortion, even at low powers, than the higher-impedance taps. He did find, however, that the LM-845IA was significantly quieter than its predecessor. Class B rating reflects high output impedance, which means performance will depend on the loudspeaker used. (Vol.44 No.7 WWW)

LSA VT-70: $1399
The LSA (Living Sounds Audio) VT-70 uses a pair of 12AU7s and a single 12AX7 for the low-level circuitry and a push-pull pair of EL34s for each channel's output. There are 4 and 8 ohm output transformer taps, as well as headphone and preamplifier outputs. The front panel features two VU meters that, in addition to showing signal level, can be used to check tube bias. RvB found that the VT-70 produced possibly the best-reproduced male voice he'd ever heard in his listening room. He commented that the amplifier reproduced what it was given, "adding only a slight caramelish quality," though he did note that it was somewhat on the unforgiving side with overcooked recordings. The low frequencies had "real heft" but the bass still sounded "nimble." He concluded that the VT-70 "provides superlative quality for cheapskates, penny-pinchers, and the merely unwasteful...As long as you couple it with reasonably efficient speakers, it can hold its own against upmarket competitors costing several times as much." On the test bench, the VT-70 featured a very high source impedance from both transformer taps and failed by a few watts to meet its specified 35Wpc power, even at 3% THD+N, due to the circuit using a limited amount of loop negative feedback. JA concluded that "the lowest distortion will be obtained from the 4 ohm output transformer tap, especially driving impedances >4 ohms, with no significant reduction in maximum power." (Vol.45 No.10 WWW)

Marantz MODEL 40n: $2499
The Model 40n is a remote-controlled, network-connected integrated amplifier with a complete set of digital and analog inputs, including Wi-Fi, HDMI-ARC, USB, and MM phono, and can be controlled with the HEOS app. Specified continuous output power is 70Wpc into 8 ohms and 100Wpc into 4 ohms. Compared with his reference Benchmark and NAD amplifiers, KR noted that the 40n was marginally warmer with vocals. Overall, however, he found that the Marantz's frequency balance was neutral, with tight, clean bass, an open-sounding midrange, and an extended, unstressed treble. The Model 40n "incorporates everything needed for playback from any source; just supply speakers and cables," KR concluded. "The 40n is this century's answer to the AM/FM stereo receiver of the previous one." JA found that the Marantz offered excellent measured performance with all its inputs and exceeded its specified powers, clipping at 74Wpc into 8 ohms and 120Wpc into 4 ohms. However, the headphone output's high source impedance means that it is best suited to high-impedance 'phones like Sennheisers. (Vol.45 No.8 WWW)

Mastersound Compact 845: $10,495
This Italian amplifier's class-A output stages each use a single Psvane 845B HiFi Series power triode. Both 4 ohm and 8 ohm output transformer taps are provided. There are both balanced and single-ended inputs—the preamplifier stage employs long-plate JJ ECC802 triodes and TungSol 6SN7GTBs driver tubes. With sensitive DeVore Fidelity O/96 and Volti Razz loudspeakers, KM was wowed by the combination's immense soundstage, and wrote that "music had energy, speed, dynamics, punch, and depth." His conclusion? "The Mastersound Compact 845 hits all my sonic sweet spots: gorgeous, burnished tube tone, palpable instrumental texture, unerring naturalism, lush, rich, transparent midrange, solid bass, open treble, black background, precise layering of instruments and vocal—and the deepest, punchiest soundstage I've heard." Mastersound specifies the Compact 845's maximum power as 30W; JA found that the amplifier only got close to delivering this power until the distortion, which was primarily second harmonic, reached 10%! He also found that the Mastersound's output impedance was very high, even from the 4 ohm tap, meaning that the amplifier will sound different with every loudspeaker with which it is partnered. (Vol.46 No.5 WWW)

Musical Fidelity M8xi: $6999
This hefty (101lb), powerful amplifier—JA measured clipping powers of 500Wpc into 8 ohms, 650Wpc into 4 ohms—offers both analog and S/PDIF and USB digital inputs. When JVS switched from his almost six-times-as-expensive reference monoblocks, he found the M8xi's sound via its balanced analog inputs "virtually as pleasing, and spot-on neutral, albeit less transparent and airy and less precise in its depiction of acoustic space." Playing his favorite extreme-bass test track, "Electrified II" by Yello, with his demanding Wilson Alexia 2 speakers, he wrote that "even if [the Musical Fidelity's] bass wasn't as gut-shaking—even if the soundstage didn't seem to reach out to me and gobble me up body and soul—it sounded really good." Turning to the M8xi's digital inputs, JVS felt that these bettered those in the Krell K-300i. He summed up the Musical Fidelity by writing that not only was it the most powerful and least expensive of the seven integrated amplifiers he has reviewed in recent years, it was also one of the best-sounding. (Vol.43 No.10 WWW)

NAD M10 V2: $2999 $$$
The words integrated amplifier are scarcely adequate to this task: The compact (only 8.5" wide) NAD M10 incorporates the BluOS operating system/music playback app; network, Wi-Fi, and Bluetooth connectivity; analog and digital inputs; support for Tidal, Qobuz, et al.; multiroom capabilities; Dirac Live LE room correction (one hopes not the Delbert Grady sort); and a big "Gorilla Glass" display on its front panel—all this plus a 100Wpc class-D (nCore) amplifier. As for that last bit, JA expressed surprise at how good the NAD sounded, even when compared to a pair of monoblocks with a five-figure price tag. (The NAD actually offered better note definition, if not quite the same degree of deep bass extension and authority.) JA-the-listener concluded that the NAD "offers everything serious audiophiles and music lovers need to enjoy their music," while JA-the-measurer noted that "NAD's M10 packs a lot of well-engineered performance into its relatively small chassis." (Vol.43 No.1 WWW)

NAD C 3050: $1399 + $500 for BluOS module $$$
The retro-styled, class-D C 3050 LE was released in 2022 to celebrate NAD's 50th anniversary. Only 1972 Limited Edition samples were made—the company was founded in 1972—one of which was reviewed by JA. The LE version sold out quickly but was soon replaced by the standard C 3050, which is the same except for cosmetics and the fact that the BluOS module is optional, adding $500 to the price. The BluOS module works with the Spotify Connect and Tidal Connect apps. In addition to the usual line, phono, and digital inputs and speaker and headphone outputs, the C 3050 offers Direct Live room EQ, full Ethernet, USB, AirPlay 2, Wi-Fi, and Bluetooth connectivity. Analog inputs are  converted to digital. JA commented that the C 3050 LE's presentation was very similar to that of NAD's more expensive M10. "Excellent upper-bass articulation was combined with a natural-sounding midrange and clean highs. Stereo imaging was well-defined with good, if not great, soundstage depth," he wrote. With Dirac operating, he found that his KEF LS50s' mid-bass region sounded in better balance with the upper bass and lower midrange. He wasn't able to audition the the MM-compatible phono stage, but in the test lab, it offered accurate RIAA equalization, low noise and distortion, and high overload margins. The NAD slightly exceeded its specified power of 100Wpc into 8 ohms. JA's conclusion: "NAD's C 3050 LE is an excellent example of a modern, full-featured, solid state integrated amplifier. But it is its integration with Dirac low-frequency room equalization that enables it to offer pretty much everything audiophiles and music lovers need to enjoy their music at a competitive price." All that should be equally true of the non-LE vesion (Vol.46 No.4 WWW)

Naim Audio Uniti Nova: $6899 ★
The star of Naim's rebooted Uniti line, the Nova combines an 80Wpc integrated amplifier with a media player and streamer, the latter supporting Tidal and Spotify. The Nova offers Bluetooth aptX HD and Wi-Fi connectivity, and provides vTuner Internet radio as well as support for most music-file types, up to 384k PCM and DSD128. All user controls are accessible via an included remote control, Naim's downloadable app, and a full-color front-panel LCD display that KM described as "lovely," supplemented with a top-panel rotary control. Ken was enchanted with the Uniti Nova's radio function, and found its file-playing capabilities ergonomically comforting—"I was surprised by the Nova's ease of setup and practically instantaneous response"—and sonically rewarding: "file after file drove my jaw floorward as my ears reveled in the Nova's beautiful sound." KM's verdict: "the Uniti Nova is practically a bargain. Definitely, effusively, highly recommended." Apart from noting some anomalous behavior with 96 and 192kHz data—their responses were down by 9dB at the ultrasonic frequency of 29kHz—JA wrote from his test bench that "the Naim Uniti Nova's measured performance reveals it to be well sorted, as they say in the UK." (Vol.41 No.3 WWW)

Outlaw Audio RR2160MkII: $999 ★ $$$
The RR2160—or, as Outlaw Audio calls it, their "Retro Receiver"—marries a 110Wpc class-AB integrated amplifier to an FM/AM tuner of the traditional sort, along with an MM/MC phono stage. Its tone controls—yes, tone controls!—and bass-emphasis switch hark back to an era of mustaches, flared trousers, and loudspeakers with sculpted-foam grilles, yet the RR2160 doesn't skimp on modern conveniences, including Ethernet connectivity, HD radio, an MP3 input, a headphone amp with independent volume controls, and a 24/192 DAC with USB, coaxial, and optical inputs. After being broken in and warmed up, the Outlaw rewarded HR with "a generously big, warm, articulate sound." Used with a CD transport, the RR2160's Burr-Brown—based DAC didn't reach the same performance heights as more expensive outboard processors, yet nonetheless surprised Herb with its "unfettered verity." The Outlaw's MM phono inputs performed well when addressed with a good-quality step-up transformer, though HR was disappointed by the lack of adjustability in its MC inputs. And its headphone section "far exceeded" HR's expectations. Writing from his test bench, JA noted the Outlaw's "significantly" higher-than-specified output power, the admirably low output impedance of its headphone amp, and its "superb" phono stage, though he was "somewhat disappointed by the measured performance of its digital inputs." HR's conclusion: "a conspicuously good-sounding audiophile product at a ridiculously low price." New version keeps performance the same but eliminates AM radio and adds Wi-Fi. (Vol.40 No.12 WWW)

Pathos InPoL Remix MkII: $5495
This elegant-looking, hot-running integrated uses a pair of Electro-Harmonix ECC88 tubes for voltage gain followed by Vishay n-channel MOSFETs biased into class-A in a bridged configuration for current amplification. The Italian manufacturer calls this loop feedback-free, bridged topology "doubleInPoL." There are four RCA input jacks; one set of balanced XLR inputs; two pairs of pre-out jacks, one RCA, one XLR, and a headphone output. An optional DAC module adds $675 but was not fitted to the review sample. KM found that the Remix worked well with his high-sensitivity, easy-to-drive DeVore Fidelity O/96s, manifesting all its considerable tone, resolution, and drive. The amplifier "presented large, focused, well-defined images with charged, bristling outlines." He felt that the bass was a little soft-sounding, but its strongest trait is its clear, open, communicative midrange, he wrote, adding that the amp's treble is part of its "pleasing, sparkling, high-energy personality." However, KM did note that the treble could sound a little hot with some music. The Remix MkII is specified as delivering 25Wpc into 8 ohms and 38Wpc into 4 ohms. In the test lab, JA found that the amplifier gave 30Wpc into 8 ohms at 3% THD+N and 38Wpc into 4 ohms at 6.5% THD+N. He concluded that this amplifier would work best with high-sensitivity, high-impedance loudspeakers like KM's DeVores, but was concerned by its inability to drive low impedances without what he felt to be excessive levels of harmonic distortion. (Vol.46 No.1 WWW)

PrimaLuna EVO 400 Integrated: $5595
The Dutch company's new top-of-the-line integrated tube amplifier uses six 12AU7 mini triodes and four pairs of EL34 output tubes, which can be operated in Triode or Ultralinear mode. (Higher-power KT-150s can also be used.) The EVO 400 offers 4 ohm and 8 ohm output transformer taps and there are also headphone, tape monitor, and line-level subwoofer outputs. (An optional moving magnet phono stage costs $249 but wasn't fitted to the review sample.) The circuitry is almost entirely hard-wired—no printed circuit boards are in the signal path. RvB commented on the PrimaLuna's extraordinary clarity and detail retrieval. He compared the two output tube modes and wrote that Ultralinear provided the clearest lens into the music, Triode taking the edge off. At low frequencies, he sometimes heard less control in the bass than he does with solid state amplifiers. "But the music chugged and jived in ways that left no room for disappointment," he noted. The EVO 400 is specified as offering maximum powers of 38Wpc into 8 ohms in Triode mode and 70Wpc into 8 ohms in Ultralinear mode. JA measured 63Wpc into 8 ohms at 1% THD+N in Ultralinear mode, and the specified 70Wpc at 3% THD+N. In Triode mode, the 8 ohm tap gave 33Wpc. JA concluded that the PrimaLuna EVO 400's measured performance was what he would expect from an amplifier with a push-pull output stage that uses paralleled EL34 tubes. The test results suggest that the lowest distortion will be obtained from the 4 ohm tap in Ultralinear mode. (Vol.45 No.6 WWW)

Rogue Audio Pharaoh II: $3995
The Pharaoh II uses Hypex's NCore NC500 modules for its class-D output stages, powered by a hefty linear supply. Two 12AU7 tubes are used for the amplifier's line stage, and three low-noise, JFET-input OPA2134 dual op-amp chips are used for the phono section. The specified maximum power is 250Wpc into 8 ohms and 400Wpc into 4 ohms; JA measured 240Wpc and 380Wpc, respectively. HR found that the amplifier sounded best after being powered up for two days, when he noted that the sound was "elegant and pristine, with exquisite fine detailing set against silent backgrounds." He also noted that the Pharaoh II's line-input transparency was noticeably better than that of Rogue's Sphinx V3. With an LP of small-scale Dowland works, HR commented that the phono input was "pure of tone, clear as water, and light on its feet." He summed up the Pharoah II by saying it "delivered enough quiet, clear, clean, effortless class-D power to drive the hard-to-drive . . . GoldenEar BRX and the current-sucking Magnepan .7 speakers," adding that the Pharaoh II's phono stage was the best he'd ever found in an integrated amp. (Vol.45 No.12 WWW)

Rogue Audio Sphinx V3: $1595
Descended from the original Sphinx that HR reviewed in 2014, the V3 is still "an old-school, 25lb, made-in-America integrated amplifier with three line-level inputs...and a 12AU7-based, mu-follower preamplifier stage driving a 100Wpc (into 8 ohm), class-D, solid state power amplifier." The phono stage now has adjustable loading and gain so it can be used with both MM and MC cartridges. (The RIAA correction incorporates the IEC-recommended low-frequency rolloff, reaching —3dB at 30Hz.) Headphone output is now based on discrete MOSFET devices, which JA found led to a very low source impedance, appropriate even for low-impedance cans. With CDs, HR found that the Sphinx V3 "delivered a good amount of leading-edge bite and trailing-edge flow. Bass felt quicker and more articulate. The V3 displayed a fun, taut energy the original did not have." He tried the phono input with the Ortofon 2M Black moving magnet and Hana EL moving coil cartridges and concluded that "The Sphinx V3's MM/MC phono input did proclaim the virtues of analog." HR summed up the V3's headphone amp as "not as powerful, dynamic, or transparent as the Schiit Ragnarok's, but it's closer to that than any others I've auditioned." Overall, he summed up the Sphinx V3 as "an unpretentious working-person's amplifier. It delivers music with an eager expressive energy, in concert with a forgiving musical nature." On the test bench, the V3 didn't quite meet its specified power, clipping at 96Wpc into 8 ohms, and the phono stage's RIAA equalization was slightly mismatched between the channels, with the right channel up to 0.9dB higher in level in the treble than the left. (Vol.43 No.8,Vol.46 No.2 WWW)

Technics SU-G700M2: $2899.95
This relatively affordable sibling of Technics' SU-R1000, which KM reviewed in Vol.44 No.12, the SU-G700M2, retains several of the SU-R1000's essential features including JENO, LAPC, and GaN FET transistors in the Advanced Speed Silent Power Supply, though it uses MOSFETs rather than GaN FETs for the switching output stage. As well as line and MM/MC phono analog inputs, there are coaxial and optical S/PDIF digital inputs and a USB input. There is a headphone output as well as the usual speaker outputs. Streaming from Qobuz and Tidal via Roon, KM was impressed by the Technics's D/A section, commenting that he "bathed in the G700M2's warm glow of good tone, ample soundstage, forward flow, and solid dynamics allied to copious low-end and detailed treble." He added that while the amplifier imbued files with a sense of warmth, it wasn't overly colored. He also liked the way in which the phono input was sufficiently transparent to reveal the differences between different pressings of the same album. "The G700M2 is a warm-blooded, even-keeled, dynamic, capable amplifier," he concluded. It offers "ample power, robust build, and good value." On the test bench the amplifier exceeded its specified maximum power of 70Wpc into 8 ohms and 140Wpc into 4 ohms, clipping at 80Wpc into 8 ohms and 148Wpc into 4 ohms. JA found that the phono input offered respectable measured performance, especially in its high overload margins. However, he was disappointed by the fact that the analog phono stage and headphone outputs were contaminated with ultrasonic noise. He also noted the presence of high-order harmonics in the loudspeaker output. Available in black or silver. (Vol.45 No.7 WWW)

VAC Sigma 170i iQ: $10,000
American-made, well-finished integrated amplifier uses KT88 output tubes in autobiased Ultralinear, push-pull configuration with 2–4, 4–8, and 8–16 ohm output transformer taps. (These are wired in inverted polarity.) Preamplifier stage and optional MM/MC phono stage use 12AX7s. JMu felt that the VAC 170i iQ's sound quality featured a sweet treble, excellent midrange, musicality, and bloom and commented that timbres were more natural than warm, and that bass was substantial, with good definition. "The VAC amp seemed more powerful than its rating suggests, and often delivered solid attacks," she concluded. The Sigma 170i iQ's maximum power is specified as 85Wpc into 4, 8, or 16 ohms. However, on JA's test bench, the VAC amplifier delivered 11.8Wpc into 8 ohms at 1% THD+N and 51Wpc into 8 ohms at 3% THD+N from the 8–16 ohm output transformer tap. Higher powers were available from the 4–8 ohm tap—32.6Wpc into 8 ohms (1% THD+N) and 79Wpc (3% THD+N). The 2–4 ohm tap was probably optimal for real loudspeaker loads, felt JA, as it reached 3% THD+N at 53Wpc into 8 ohms and 75Wpc into 4 ohms. However, the Sigma 170iQ's output impedance was high, especially from the 8–16 ohm tap, meaning that its sound quality will be different with every loudspeaker it is used to drive. Phono input features accurate RIAA equalization, but low overload margins at low frequencies mean that low-output phono cartridges will work better with this input. (Vol.44 No.4 WWW)

Vincent SV-737: $3499.95
Designed in Germany and made in China, this relatively affordable but versatile integrated combines a tubed input stage with an output stage biased to deliver the first 10W of the maximum 8 ohm power of 180W in class-A. The single AEG 85A2 tube that peers out from the faceplate window is a professional gas stabilizer tube, an integral part of the high-voltage power supply regulation for the preamplifier. The preamplifier stage uses two 6N1P and two 6N2P tubes, offers tone controls, and is fed signal by six pairs of single-ended line inputs. Another pair of single-ended inputs feeds the power amplifier stage directly. Digital inputs include three S/PDIF (one optical, two coaxial), Wi-Fi, and Bluetooth. As well as speaker outputs, the Vincent has preamplifier and headphone outputs. "Out of the box, the Vincent wowed with crisp transients, detailed treble, neutral upper mids, rich, lush lower midrange, and powerful bass," wrote KM. While he found the amplifier largely transparent from the mids up, the Vincent "added a pleasing extra dollop of energy, warmth, and color down low." He liked the sound of the S/PDIF digital inputs, which produced "gobs of air, refined, corporeal images, and a deeper soundstage" compared with his reference Tascam CD player. JA found much to admire in the amplifier's measured performance, though he felt that the digital inputs and headphone output should be regarded as more for convenience than for absolute performance. He also found that the SV-737 didn't quite meet its specified power, delivering 155Wpc into 8 ohms and 240W into 4 ohms at 1% THD+N with both channels driven. However, it appeared that one of the review sample's left-channel tubes was starting to fail; while the right channel offered very low levels of distortion, the left channel's THD was almost 20 times higher, at 0.1% across the band. (Vol.44 No.7 WWW)

Western Electric 91E: $14,999 in Black or Champagne; $15,999 in Nickel
This amplifier from the reborn Western Electric company is an intriguing mix of modern technology—the microprocessor-controlled tube biasing and volume control, the comprehensive front-panel display, the patented Steered Current Source (SCS) technology—and single-ended 300B output tubes, the design of which dates back to 1938. The single output transformer tap is optimized for 8 ohm loads. (Optional 4 ohm and 16 ohm transformers are available for $999 each.) KM was impressed by the 91E's low frequencies, which he described as "tight and accurate." He found that the Western Electric delivered "sweet'n pure triode-treble," which he characterized as "(largely) grain-free." He summed up his auditioning by saying "The 91E is not your traditional treble-and-midrange-champ SET amplifier. In delivering more strength and power without compromising the low end, it's a classy machine that can frame music neutrally in a large soundstage." The 91E's MC/MM phono stage uses op-amp chips and offers a choice of resistive loadings. JA found that the phono stage offered low noise and distortion and accurate RIAA EQ, though he felt that, overall, the amplifier's measured performance was dominated by its use of a single-ended output stage with a 300B tube and no loop negative feedback. The 91E met its specified power of 14Wpc into 4 ohms at 10% THD+N, this predominantly the second harmonic. "Given its high levels of both harmonic and intermodulation distortion, even at lowish powers," he wrote, "it will work best with loudspeakers that have a 4 ohm nominal impedance and high sensitivity." (Vol.45 No.11 WWW)

C:

Bluesound Powernode: $949 $$$
The fourth iteration of this Canadian-designed, Chinese-manufactured, Roon Ready, MQA- and AirPlay 2—capable, class-D streaming amplifier is more powerful than its predecessors. (JA found that it met the specified continuous maximum power of 80Wpc into 8 ohms but didn't deliver higher powers into lower impedances.) Controlling the amplifier with the BluOS app and pairing it with GoldenEar BRX loudspeakers, KM wrote that he was delighted with the sounds the Powernode produced. "The amp struck a good balance of richness and crispness, scale, and density," he noted. With the full-range DeVore O/96 speakers, the Powernode didn't sound as natural and flowing as his reference separates, but KM commented that its clarity and soundstaging were strong, "especially so for an amp that costs so little." He was also impressed by its headphone output and summed up his time with the Powernode by writing "like the original NAD 3020, circa 1980, the Bluesound Powernode is the everyman's (or everywoman's) integrated amplifier for its own time." JA noted that the Powernode digitizes its analog inputs but found that its digital inputs offered good measured results. He concluded that while, to some extent, the Powernode's measured performance is affected by noise contamination from the class-D output stage, overall it did well on the test bench, especially considering its affordable price. (Vol.45 No.6 WWW)

Peachtree Audio nova300: $999 ★
With their nova300 integrated amplifier-DAC, Peachtree Audio made a number of transitions: from iPod docks to Lightning connectors and Wi-Fi; from tubed preamp buffers to all solid state; from line-only preamps to an onboard MM phono preamp; and, most notably, from Chinese to Canadian manufacture. Other characteristics endure, including the attractive wood wrap—made even more attractive by an Ebony Mocha finish option—and a class-D output stage, this one based on ICEpower modules, for a power rating of 300Wpc into 8 ohms. The nova300 also boasts double-DSD capability alongside 32/384 PCM, and Peachtree's Dynamic Noise Elimination (DyNEC), which is claimed to eliminate, among other noises, those associated with the display screens of smartphones and tablets. In a review that proved controversial, AD praised Peachtree Audio for the nova300's excellent phono section and for its overall good momentum and drive, but criticized the graininess of its treble range. In their Manufacturer's Comment in the same issue, Peachtree took issue with Art's pairing of the nova300 with his extremely efficient Altec Flamenco speakers, calling it a "mismatch," though they held out the possibility of a flaw in the review sample, which they said was "on its way to our engineers for a testing, just in case." We were disappointed never to have heard back about the first sample, which, in his measurements, JA described as having "a high level of switching noise on its output." However, for the December 2017 Stereophile AD wrote a Follow-Up based on a second sample of the nova300, which he tried with the very contemporary Wharfedale Diamond 225 speakers. Art thought this pairing sounded "slightly less edgy" than his earlier experience, although the sound remained "dry and crisp overall." One of RvB's reference amplifiers. (Vol.40 Nos.6 & 12 WWW)

Deletions
Raal-requisite HSA-1B, discontinued. Cary Audio SLI-80HS, Devialet Expert 140 Pro, Luxman SQ-N150, NAD C 328, Quad Artera Solus Play, Schiit Ragnarok 2, replaced by model not yet reviewed.