Recommended Components

A:

Audio Research Reference 6SE: $19,500
An updated version of the discontinued Ref 6, with changes in capacitors and wiring, the fully balanced, tubed '6SE impressed JVS, who noted that when he installed the Ref 6SE in his system, his speakers "poured forth some of the most polished, transparent, and arresting sound" he'd heard from his system. Longer-term listening, however, indicated that the Audio Research preamplifier was sensitive to setup issues. Once he had optimized everything else in his system—cables, footers, stands, AC supply—JVS could report that the Ref 6SE's "warmth and vibrancy of color, prominent midrange, and seemingly more dramatic dynamic contrasts made me want to listen more and deeper." In a Follow-Up, JA felt the Ref 6SE's sonic signature, with its slightly softened highs but superb resolution of recorded detail, would work best with systems that are a little laid-back in the upper midrange and that don't have underdamped or poorly defined low frequencies. (Vol.43 No.11, Vol.44 No.8, Vol.45 No.10 WWW)

Audio-GD Vacuum HE1 XLR balanced: $3999
See Herb Reichert's review in this issue. (Vol.46 No.10 WWW)

Benchmark LA4: $2950 w/o remote; $3050 with remote $$$
Benchmark's usual approach to design is to out-spec the competition, and so it is here. Like other Benchmark equipment he has tested, the affordable LA4 challenged the resolution of JA's test instruments, with "superb" channel separation, "extremely low noise, and virtually no power-supply-related spuriae." Restricting his measurement to the audio band, JA found an "astonishing" S/N ratio of 105.5dB for both channels; it remained extremely low across the audioband. He summed up: "Benchmark's LA4 is the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered." In his listening room, KR compared the LA4 to a cable—and couldn't hear any difference. He concludes, "the LA4 is probably the most transparent and revealing audio component I've ever used. It does not seem to leave any fingerprints on the sound." See also HR's review of Benchmark's similar HPA4 headphone amplifier (see "Headphones" ). JA found that the LA4 had a more upfront presentation than the MBL N11 or Pass Labs XP-32, with less soundstage depth apparent on his own recordings. (Vol.43 Nos.1 & 11, Vol.44 No.3 WWW)

Bryston BP-17³: $4995 ★ $$$
With its five single-ended inputs, two balanced inputs, and mix of single-ended and balanced outputs, the solid state BP-17³ is the middle model of Bryston's three line-level preamplifiers. It can be customized with a variety of add-ons, including a MM phono stage ($750), a DAC ($750), and a remote-control handset ($375). Used with a Mark Levinson No534 power amp (see "Power Amplifiers"), a fully equipped BP-17³ delighted LG with its ability to preserve bass weight and solidity when called for and its no—less impressive recreation of recording-hall ambience. LG wrote that the Bryston "produced engaging, detailed, tonally captivating, utterly natural sound that approached reference quality," while noting that matching with the correct amplifier is critical. JA's report from his lab on the "superbly well engineered" Bryston was similarly to the point: "It is difficult to see how a preamplifier could perform any better on the test bench!" Tests of phono and DAC modules also fared well. (Vol.41 No.6, Vol.42 Nos.6 & 7 WWW)

Dan D'Agostino Momentum HD: $42,500
The two-piece Momentum HD—its power supply is contained within its stand—is an all-balanced, fully discrete, line-level preamplifier with six inputs and two outputs, all via XLR connectors. As with the original Momentum, the HD's aesthetics keep pace with the designs of other D'Agostino creations: Here, the dial at the center of the front panel is a green-lit volume meter, its bezel the volume "knob." Once installed in JVS's system, the Momentum HD brought to a favorite recording of the Shostakovich Symphony No.11 "deeper and more resonant bass and an all-enveloping three-dimensional soundstage that was as thrilling as it was terrifying." He added, "with the Momentum HD, a new window opened, and every recording became a source of wonder." Writing from his test bench, JA noted that the Momentum HD fell slightly short of its predecessor in a few aspects of measured performance yet distinguished itself as "a well-engineered preamplifier." (Vol.43 No.2 WWW)

darTZeel NHB-18NS MKII: $61,000 ★
The "stunningly transparent" darTZeel NHB-18NS of 2007 offered spectacular transient speed, resolution, and decay, while providing an overall coherence that "made recorded music, analog or digital, sound much closer to live," according to MF, who added that, with its warm, vivid combination of red case and dark-gold front and rear panels, the NHB-18NS "looks like it sounds." As of the summer of 2008—by which time he'd bought one for himself—MF felt that the battery-powered NHB-18NS matched the resolution and transparency of MBL's 6010 D preamp while managing to sound less mechanical. The NHB-18NS of 2017 is a complete redesign of the Swiss company's preamp, but it still offers both line and phono stages—the latter, per MF, being "sonically far superior to the original" and more adjustable than many outboard phono preamps of his experience. MF also hailed the new model's digitally displayed volume-control calibration and the fact that, unlike those of its predecessor, the new model's batteries "have never run out of juice during a listening session." According to Mikey, the new darTZeel's phono section sounds "neither as transparent nor as dynamic" as the CH Precision P1 phono preamp ($31,000 without additional power supply) or Ypsilon VPS-100 Silver Edition ($65,000). Yet, with the "tube-like richness and generous flow" it inherited from its forebear, the 18NS "will more than satisfy casual vinyl listeners." The major difference between the original NHB-18NS and the new version was the replacement of the transformer-coupled balanced inputs and outputs with a direct-coupled topology. JA found that the balanced output impedance was usefully much lower than the original version's. While distortion was very low, the noisefloor was higher than JA expected, and there was an odd rise in the noisefloor in the mid-treble. The MC input offers adjustable gain and input impedance, an optional subsonic filter, and so-called Neumann 4th pole equalization. JA recommends the latter be switched off—without it the RIAA deemphasis is superbly accurate. (Vol.30 No.6, Vol.31 No.10, Vol.33 Nos.5 & 10, Vol.40 No.6, Vol.45 No.2 WWW)

Engström MONICA Mk3: $60,000
This very expensive, two-chassis, tubed line preamplifier from Sweden houses the transformer-coupled analog circuitry with its 48-step volume control in one chassis, the power supply, display, and control circuitry in the other. The review sample's preamp chassis used four NOS 5687WB small-signal tubes; the power supply used one ECC83 tube and one 6080WC tube. There is no remote control; the preamp can be controlled by Engström's iPhone/iPad app. JVS wrote that the Engström's tonal saturation and completeness sounded 100% right" and concluded that the Monica Mk3 preamplifier "is as complete a musical instrument as I've ever welcomed to my music room. It doesn't hit you over the head with its strengths; rather, it unfailingly seduces with the inherent rightness of its sound and presentation." With the preamp on the test bench, JA wrote that the Engström Monica Mk3's measured performance is dominated by the designer's decision not to use negative feedback, which gave rise to modest amounts of mainly low-order harmonic distortion. He was impressed by the fact that the preamplifier was not fazed by driving low impedances, but was puzzled by the Engström's boosted response at ultrasonic frequencies, which could mean that the preamplifier might be susceptible to picking up RF interference. (Vol.45 No.4 WWW)

Esoteric Grandioso C1X: $46,000
When tastefully illumined by the adjustable blue LED lighting of its separate power supply, the dual-mono, fully balanced Grandioso C1X line preamp "looks like a million dollars—which, given its healthy price tag, it should," wrote JVS. But even if Esoteric's attention to detail had not convinced him that the C1X was a class act, its sound would have, and did. "The C1X delivered bass every bit as mouthwatering and thrilling as I've come to expect from my system," he wrote. Overall, the Grandioso C1X "could very well be the keeper, the component that delivers a lifetime of joy and pleasure," he concluded. "It is one of those rare products whose excellence is proclaimed with every note. It is more than an object of beauty; it reaches into the emotional core of musical experience and opens a window onto ultimate truth." JA was similarly impressed when he got this Japanese preamplifier in his test lab, writing "Esoteric's Grandioso C1X offered superb measured behavior. Its extraordinarily low levels of distortion and noise rival the performance of contenders from Benchmark, MBL, and Pass Labs." Asked for his rating, JVS says, "If there's an A+ category, it belongs there." There isn't.(Vol.44 No.7 WWW)

Gryphon Commander: $67,000
This unusually large, heavy, expensive, two-chassis, dual-mono, solid state line-level preamp features a 4.3" proximity-sensing TFT touch screen that controls all of its functionality, including an 85-step, microprocessor-controlled volume control. (There is also a remote control.) The Commander has four pairs each of balanced and single-ended inputs and two pairs of balanced (XLR) outputs and one single-ended output pair—plus another stereo output pair labeled "TAPE." After the preamp had been run in for six days, MF felt its sound was precise, pleasingly taut, and well-focused, with immediately impressive image three-dimensionality. "Vital" was the one-word description that came to his mind. "Even for this seasoned veteran," MF concluded, "every listen demonstrated that the Commander did as promised, allowing (rather than producing) exceptionally transparent, fast, natural, open sound from all source components. It was as close to a neutral-sounding audio component as I've had in my system." The Commander also excelled on the test bench, offering very low noise and very low levels of low-order distortion. (Vol.45 No.7 WWW)

HoloAudio Serene KTE: $3098
HR found that this "supertransparent" solid state line preamp enhanced the sound quality with every source he tried: "The Serene gave the May a dose of sunlight and a shot of adrenalin. [It added] grace and liquidity to the sound of the Mola Mola Tambaqui and punch and bass authority to the Denafrips Terminator Plus." He also noted that it enhanced the spatial presentation of Sutherland Engineering's Little Loco phono stage—"adding force and rhythmic nuance while peeling away a layer of shadow that had previously obscured the perimeters of the Loco's projected soundscape." (Vol.45 No.6; Vol.46 No.1 WWW)

Lab12 Pre1: $2290
This line stage from Greece uses a single high-transconductance, twin-triode, E88CC tube per channel without any loop feedback to give a high maximum gain of 21dB. It offers five line-level (RCA) inputs and two outputs: one RCA, the other XLR. HR found that compared to PrimaLuna's tube-rectified EVO400, the Pre1 sounded turbocharged. "Could this be the difference between solid state and tube rectifiers?" he wondered. Compared with HoloAudio's higher-priced KTE Serene, HR noted that the Pre1's clarity/transparency/invisibility was equal to that of the Serene but the Pre1's transparency was less stark than the Serene's, "breathier and more vibrant with a slight, just-right aura of tube radiance." He also found that the Pre1 couldn't match the Serene "for low-end gut-punch, upper-bass detail, or dynamic swagger." However, using the Pre1 to drive Genelec's G Three active loudspeakers, HR realized that he was experiencing "a more refined, grainless, 'invisible' preamplifier than any I could recall using." (Vol.46 No.1 WWW)

Luxman CL-1000: $23,995
AD described the massive, full-function CL-1000 as the "antithesis of a bare-bones, 'purist' preamplifier." It uses six E88CC dual-triode tubes in its transformer-coupled output stage, as well as FETs in the single-input phono stage and solid state devices in the power supply's rectification and regulation circuitry. One thing lacking was a remote control, much to AD's joy! Playing LPs, the Luxman appeared to have a flatter frequency response than Art's reference Shindo Monbrison preamplifier and sounded altogether more serene—"but along with that," he wrote, "was also a sense that the Luxman's audible range was a bit more spread out, from bass to treble." AD's auditioning notes included such comments as "Listening to this record through the CL-1000 was a spellbinding, wholly engrossing experience" and "The music had flow and, where appropriate, drive." The Luxman "is simply a hell of a good product, at a high but not unreasonable price," concluded AD, adding "I loved every minute with it." (Vol.43 No.5 WWW)

MBL Noble Series N11: $17,700
This beautiful, multiple-input, multiple-output line preamplifier can be used in its Unity Gain mode for maximum sound quality or with a higher-gain setting. JVS found that the N11 in its higher-gain mode "brought out the warm core of every note," adding that it enabled him to hear "the subtle differences of interpretation, dynamics, and color that are the portals to the truth behind the notes." He found that Unity Gain moved the soundstage farther back in his system with his D/A processors. While perspective was clarified, this mode made the sound less open with slightly reduced transparency and bass. Ultimately, he felt that the N11's Unity Gain "toned down the noisy top ends of some recordings, making for easier listening." The N11's measurements revealed extraordinarily low noise and distortion, especially in Unity Gain mode. However, the CD input's unbalanced impedance of 2.3k ohms will tax sources with a tubed output stage. Those can be used with the balanced inputs or the unbalanced Aux inputs, which have impedances of 10k ohms and 47k ohms, respectively. To his surprise, JA found that inserting the N11 between his DAC and power amplifiers resulted in a more palpable presentation, with a deeper soundstage. (Vol.43 Nos.7, 11 & 12; Vol.44 No.3 WWW)

Pass Labs XP-32: $18,375
Replacing the well-regarded XP-30, the three-box XP-32 looks almost identical. To minimize noise, each channel's audio circuitry is housed in a separate chassis with the "dirty" control and power-supply circuitry in a third. Internal improvements include new transformers and DC-coupling of the balanced and single-ended inputs. The output stage runs a higher class-A bias with lower output impedance than the XP-30, and the volume control now operates in 0.5dB steps rather the earlier preamp's 1dB steps. JA was enthralled by the XP-32's transparency, hearing small details in his own recordings that he had not been fully aware of before. "A great preamplifier will allow through so much information, so much of the music, that the shortcomings of lesser speakers and amplifiers can be forgotten. The Pass Labs XP-32 satisfies that definition," he concluded. In a follow-up, JCA compared the XP-32 with the two-chassis XP-22. He was impressed with what he heard: "The XP-32 was just slightly more explicit than the XP-22. It was immediately noticeable on any music I played," he wrote, concluding that he "thought the XP-22 preamplifier let through all the music, or all that mattered, but I guess it didn't, because the XP-32 lets through just a little bit more." (Vol.44 No.3, Vol.45 Nos.4 & 6 WWW)

PrimaLuna EVO 400: $5295
PrimaLuna's brand-new flagship line-level preamp—it replaces the company's DiaLogue Premium—the EVO 400 uses tubes for rectification as well as for gain and buffering, and includes input and output transformers that allow balanced operation. Noting that its extraordinary weight (52.8lb) comes not from its steel chassis but from its abundance of power-supply transformers and chokes, HR praised the EVO 400's very high parts quality and lavished similar praise on its "scintillating" presentation and ability to portray vivid, well-saturated musical colors while nevertheless being "more concise-sounding" than its predecessor in the PrimaLuna line. "It generated clearer, more muscular presentations with sharper focus and more distinctly punctuated momentums." Reporting from his test bench, JA noted that "the EVO 400 measures well for a tubed design." (Vol.46 No.1 WWW)

Primare PRE35 Prisma: $5000
The basic PRE35 Prisma preamplifier lists for $3900. The DM35 DAC module adds $500 and the SM35 Prisma network module adds $600, and you have the Primare PRE35 Prisma. There are balanced and single-ended analog line inputs. Digital inputs include four TosLink, two S/PDIF on RCA, one USB-A, one USB-B, one LAN/Ethernet), and Wi-Fi and Bluetooth antennae. There are two balanced and two unbalanced outputs, one digital output (S/PDIF on RCA), and a LAN output. The DAC chip is a premium AKM AK4497EQ. The PRE35 can be controlled with the multiroom Primare Prisma app, which is available for iOS and Android. The app facilitates component setup, integrates internet radio, allows access to music files stored on your local network, and provides links allowing you to access local streaming services via Chromecast, AirPlay, Bluetooth, and Spotify Connect. Qobuz and Tidal integration were imminent at the time of the review. On first listening SM felt that the sound of the PRE35 Prisma was very close to that of his reference Audio Research REF6SE preamplifier, though "deep lows were more forward on the PRE35, the highest highs audible to me a little brighter—in other words, voiced a little differently at the extremes." Overall, after extended listening SM was impressed, concluding "The Primare PRE35 Prisma is a finely honed, well-made, and—considering the state-of-the-art technologies it incorporates—fairly priced streaming preamplifier. Its simple Scandinavian aesthetic belies its rich functionality and flexibility." JA was equally impressed by the PRE35 Prisma's measured performance, offering very low distortion and noise for both analog and digital input signals. (Vol.46 No.4 WWW)

Rogue Audio RP-7: $4995 ★
This line-level preamplifier uses four 12AU7 dual-triode tubes and contains 17 (!) separate power supplies, including an individual regulated filament supply for each tube. Its military-spec circuit board is endowed with heavy copper traces and graced with an abundance of Vishay HEXFRED diodes, Vishay resistors, and Mundorf oil-caps. The Rogue's rear panel is itself abundant with connectors: three unbalanced (RCA) line-level inputs, two balanced (XLR) line-level inputs, and two each unbalanced and balanced outputs, following the same connector conventions. The front panel is notable for more than just its single 1/4" headphone jack and its old-school volume knob: It also includes a Balance knob, which HR loved. Used in conjunction with HR's First Watt SIT-3 solid state amplifier, the Rogue preamp delivered "a superbly balanced and invigorating—nay, intoxicating—system that didn't sound like tubes or solid state. But it did reproduce, with extraordinary weight and saturated tones, my latest favorite piano album." Herb's conclusion: "My new reference." In measuring the RP-7, JA found that, "as long as it's driving a power amplifier with a high input impedance, Rogue's RP-7 offers generally respectable measured performance." (Vol.42 No.3 WWW)

Schiit Freya+: $849 without tubes, $1049 with 6SN7 tubes or LISST, $899 with NOS 6N8S tubes
This compact line stage uses four Tung-Sol 6SN7GTB tubes and offers two pairs of balanced XLR inputs, three pairs of unbalanced RCA inputs, one pair of XLR outputs, and two pairs of RCA outputs, as well as a remote control. There are three operating modes: solid state buffered; passive; and tubed active, which offers 12dB of gain. KR found that the SS buffer gave enhanced soundstage depth compared with passive mode, where the music was marginally drier and smaller. Tubed active mode in general sounded a little warm, rich, and forgiving—all attributes sought by many. "The bass was rich and weighty, which I found quite enjoyable for passive listening," wrote KR, "but I preferred the solid state buffer mode for its uncolored directness." His conclusion? "The Freya + delivers high-quality sound and reliable operation at a very friendly price. Each of the Freya's modes will appeal to specific listeners, but, very likely, many will enjoy having all the options." JA was impressed, writing "With its very low levels of both noise and distortion, even with the tube stage active, the Schiit Freya+ preamplifier's measured performance is superb, matching or better than the specifications listed on Schiit's website." His only caution was that the high output impedance at low frequencies from all the outputs will result in a lightweight balance with power amplifiers that have an input impedance much below 10k ohms. After a brief trial at home (which he has not yet written up), JCA is tempted to downgrade the Freya + due to nonsonic factors, in particular excess heat and mediocre, difficult-to-interpret front-panel controls. Almost, but not quite. (Vol.45 No.4 WWW)

Sugden Masterclass LA-4: $4650
Sugden's solid state, line-level-only Masterclass LA-4 offers four single-ended (RCA) inputs and one balanced (XLR) input, with outputs of both of those types. (The circuitry is fully balanced overall.) Gain is generous—JA would measure ca 20dB, single-ended or balanced—with signal attenuation courtesy of an old-school volume control. With the Sugden in his system, JCA noted "more ambiance with good recordings" than through his reference PS Audio preamp, but also "a touch less body." Overall, the Masterclass LA-4 "subtly illuminated the music" and "preserved subtle soundstage cues." JA's measurements uncovered lower-than-specified output impedance, thus indicating good compatibility with a variety of power amps, but a "disappointing" wideband S/N ratio. (Vol.42 No.4 WWW)

Topping Pre90: $599 plus $249 for the Ext90 input extender
This affordable solid state preamplifier comes with a remote control and one pair each of balanced and unbalanced inputs and outputs. The optional $249 Ext90 adds one RCA and three XLR input pairs. Circuitry is all balanced. There's no balance control, but the volume control operates in relay-controlled 0.5dB steps. "A transparent, noise-free sound," decided KR, who described the Pre90 as "a great bargain." JA warned that the balanced input has very low impedance—1000 ohms—which will give a bass-light balance with source components that have a tubed output stage. But with its extraordinarily low levels of noise and distortion and very high channel separation, he concluded "the fact that that performance can be achieved in such a small chassis and for such a low price suggests that Topping has some serious audio engineering talent in-house." On Amazon, price now includes the Ext90 output extender. (Vol.45 No.2 WWW)

Woo Audio 3ES: $8999 (standard version)
See "Headphones & Headphone Accessories." (Vol.45 No.1 WWW)

Zesto Audio Leto Ultra II: $11,900
This well-engineered, tubed line preamplifier offers single-ended, transformer-coupled balanced inputs and outputs. A unique "Presence" control knob applies high-frequency rolloff with five choices of corner frequency. KM liked what he heard, writing that the Leto Ultra II was one of very few preamplifiers he's had in house that in some ways equaled his long-term reference Shindo preamplifier. "Record after record, the Leto Ultra II's neutrality, transparency, and recovery of the last iota of sustain gave fresh insight into familiar recordings," he wrote, concluding that "Superbly clean and transparent, the Leto Ultra II's midrange-to–upper treble focus and lucidity was off the charts, giving fresh insight to familiar LPs. Silky and smooth, its tone was also good." In a Follow-Up, JCA explored the effect of the Presence control and found that the top three settings, which progressively roll off the top octave, were beneficial with recordings that had highs that had been balanced on the hot side. JCA was also impressed by the Leto's overall performance, writing: "This is a preamp that wears its tubed nature lightly, imparting a slight creaminess on the sound while giving up little in the way of transparency. Instrumental timbres remained natural and soundstage depth was preserved." (Vol.44 Nos.2 & 9 WWW)

B:

Ferrum OOR: $1995
See "Headphones & Headphone Accessories." (Vol.45 No.2 WWW)

Deletions
Rotel Michi P5, replaced by newer model not yet reviewed. Pass Laboratories XP-22, not auditioned in a long time.