In some ways it is very close to the best $1800 pair I've ever heard (all music). JA, writing from his test bench, painted a somewhat different view, having found an ultrasonic response peak, a linear increase in distortion with increasing power output, and a failure to meet the power-output specs with less than 2% THD. Another, very different panel speaker came next: "Driven by the Pass Labs XA25, the Magnepan .7s did real-life natural with ease and élan." (Vol.41 Nos. . There’s just the right touch of harmonic lushness delivered with superb transient speed and control. He also made special mention of the ATM 300R's way with orchestral double basses, noting their "depth and power, and far greater clarity of pitch than I've heard through any other 300B amplifier, bar none." Ultimately I think I prefer the sound of a single stereo amp. (Vol.41 Nos.7 & 10 WWW), Bricasti Design M28 monoblock: $30,000/pair ★ Deletions The Emotiva Stealth PA-1 Balanced Class-D Monoblock Power Amplifier is an exceptionally great amp, regardless of price, regardless of weight, and... Power Amplifiers McIntosh Reviews: MVP901 A/V Disc Player, MX122 A/V Processor, MC205 Five-Channel Power Amplifier (Vol.40 No.7 WWW), AVM Ovation MA8.2 monoblock: $31,990/pair In a Follow-Up in September 2017, HR reported on his experience with the Bel Canto monoblocks, ostensibly borrowed to drive his current-hungry Magnepan .7s (which Herb had never heard sound "more precise, powerful, or three-dimensional" than with the post-break-in REF600Ms). Its classically elegant design features a quartet of 6CA7 valves and newly developed Hashimoto transformers. . Quoth the editor: "a powerhouse of an amplifier." Most importantly, its sound is pure and direct. A genuine masterpiece from an Old Master. But when more power is required the Cary slips into class-A2, and there the output tubes differ, the 845 delivering up to 50W for short durations, the 211 up to 70W. JA's summary: "Overall, the Mark Levinson No.536 measured very well, its performance uncompromised by its ability to deliver very high powers into low-impedance loads." This is the first PS Audio product to use this latest ICE Edge module. Capable of driving most speakers and resolving musical details well, the D200i gives music lovers a healthy portion of what Gamut’s even more powerful and highly resolving M250i mono amp sounds like, but does so at a much lower price. While the MC275's two hefty transformers utilize the same "unity-coupled circuit" invented by McIntosh in 1947, the copper wiring is now insulated in a more durable synthetic material. In fact, almost all of the colorations you’ll hear through this amp will come from the other components. The chassis is old-school minimalist, and a tube cage is supplied. Following the Theta's time on his test bench, JA wrote, "The measured performance of Theta Digital's Prometheus is superb, even for an amplifier with a class-D output stage." It conveys vocals with weight and authority. Both single-ended and balanced inputs are provided on the rear panel, while the front panel is home to a digital display that reports temperature, DC offset voltage, and various fault conditions. The bass was tight and clean, maybe slightly lean, with no overhang or fuzzy harmonic additives." (The latter is presumed to contribute to the amp's 48.5-lb weight.) ST: "I heard all the dynamic quality, all that aliveness of the original, plus a level of transparency that brings the MC275 definitely into the 21st century." Expect a substantial dose of tube magic with a good measure of tonal neutrality. Each 88-lb XA60.8 operates in pure class-A, made possible in part by the amp's massive aluminum heatsinks and no-less-massive steel mains transformers. "This is a great amplifier," he decided. Through the Inspiration offers a less expensive implementation of the Hercules’ topology, Constellation has still managed to bring the big amp’s DNA to a more affordable price. The fifth incarnation of the 75Wpc MC275, originally introduced in 1961, retains the first incarnation's classic appearance and its use of four KT88 power-output tubes, three 12AX7 input tubes, and four 12AT7 driver tubes. Apple HomePod photo came on frot page of Stereophile but it is not in Recommended List of components. "It made the Quad's legendary midrange more solid, dynamic, and well defined than I'd ever thought possible." It's fully analog, using traditional power-supply technology, and each channel's output section employs 24 bipolar output devices, for a specified power output of 125Wpc into 8 ohms. When used to drive his Wilson Sabrina loudspeakers, the DPA-1Ms impressed RD with "their clear, open sound, resolution of fine detail, dynamics, and freedom from coloration," though he felt the (more expensive) Theta Digital Prometheus monoblocks reproduced music "with more body." (Vol.38 No.8 WWW), Bel Canto Design e.One REF600M monoblock $4990/pair $$$ Measurer-in-chief JA noted output impedance high enough to have audible consequences (of the nongood variety), plus higher-than-expected harmonic and intermodulation distortion: "I was disappointed by the BorderPatrol P21 EXD's measured performance." As HR mused in his review of the solid-state AkitikA GT-102, "Jeez, Louiseshould I even bother to drive a $7700 pair of [Joseph Audio Pulsar] speakers with a $488 amp?" LG praised the No.536 for exerting "a superior grip" on the woofers of his Revel Ultima Salon2 speakers, and for reproducing deep organ-pedal notes "with unflinching control and solidity." Best Budget Stereo Amplifier: Emotiva XPA-2. The SIT-3 is a single-ended amplifier in which the input signal has its voltage gain boosted by only an onboard step-up transformer; the amp's single active stage provides only current gain. The PRIME R1200-1D is an ultra-efficient mono amplifier... Optimized exclusively for use with subwoofers (RMS Power... High efficiency, Class D … An exceptionally neutral and musical product. 4) EgglestonWorks Viginti. … Sonically, the two are very similar, sharing the Constellation hallmarks of transparency and resolution. Chimneys are used to cool the tubes by convection, and three circuit boards have been replaced by a single board on which are mounted all components, tube sockets, and power-supply parts. Herb's conclusion: "the Stereo 100 is everything . 2) Magico S5 Mk.II AD, who has "never heard a single-ended 300B amp that I disliked," was especially smitten by this compact yet remarkably heavy (54 lb) stereo amplifier: a three-stage design in which 12AU7 and 12BH7 dual-triode tubesone each per channelare used as voltage-gain stages and drivers, respectively. Wow! Aesthetix Atlas Stereo $8000 Aesthetix’s first foray into power amps is an unqualified success. . To ensure that ours was an exemplary sample, for the sake of measurements if nothing else, HR tried a factory-built sample and found the 60Wpc GT-102, which is based on the same power op-amp as the well-regarded 47 Laboratory Gaincard integrated amp, had a "warmer, darker" sound than that of his Pass Laboratories XA25. The two stages are joined by a custom-wound transformer that also serves as the phase splitter for the push-pull output architecture, and the amp is fitted with a 6CA4/EZ81 rectifier tubean oddity in an otherwise predominantly solid-state product. Basic price is $1185. Nor, at 280lb in its flight case, is it likely to "go walkin'." Each Progression Monoblock weighs a considerable 150 lb and, as JVS discovered, tends not to run more than warm to the touch: "On colder days, I still needed to heat the room." More to the point, Jason heard from the Jadis amps a sound that was "smooth, supremely well balanced, and captivatingly beautiful," though he noted that frequency extremes were not as well served as with his Passes, resulting in a lack of sparkle with some recordings, less impactful bass with others. * NAD M22 & M27 amps. No matter what style of music she played, no matter what speakers she paired it with, the Air Tight ATM-1S delivered the sonic goods with naturalness, beauty, and ease, while also throwing a remarkably deep and wide soundstage. In his Follow-Up, JA described the full set of measurements he made of the Luxman; his observations included higher-than-specified power (30Wpc into 8 ohms) and excellent squarewave reproduction ("a tribute to the high quality of its output transformers"). Named for its designer, Bascom H. King, the BHK Signature 300 is a hybrid monoblock with a tubed input stage and a MOSFET power stage, and is specified to deliver 300W into 8 ohms. Image solidity, according to DO, can only be described as magical; solid-state amps would kill for it. (Vol.42 No.1 WWW). . JA's measurements did nothing to dispel that notion: "Although [its] relatively high level of second-harmonic distortion, which is a deliberate design choice, is controversial, the First Watt SIT-3 is a well-engineered amplifier." (Vol.40 No.2 WWW), Bricasti Design M15: $18,000 The H30 can be operated in bridged mode for 1000W, but some of the midrange magic disappears and resolution slightly diminishes. Nevertheless, even within each subclass, Class A amplifiers differ sufficiently in character that each will shine in an appropriate system. Rather, the immense power reserves mean that it is never stressed, no matter how complex or demanding the music. JA concurs. Power-supply rectification is solid-state, and output transformers, mains transformer, and power-supply choke are all designed and made by Luxman. Sanders Sound Magtech $5500 This no-nonsense amplifier was designed to drive any loudspeaker load, particularly full-range electrostatics, which can have an impedance of less than 1 ohm in the top octave. In KR's words, the M22 "is more than fair value in view of its compact size, excellent build quality, the wallop necessary for staggering volume levels, a tolerance for driving difficult loads, and, most of all, its transparent sound." In his Follow-Up, JCA observed that "the Lamms didn't bring out every tiny nuance . Consequently, the 2150 runs relatively cool. In his listening observations, AD expressed a preference for the 845 tubes, but noted from both tube types a bass range that was slightly too generous but nonetheless sublime, giving impact and taut tone to timpani and rewarding him with electric-bass lines that were always engaging and never sluggish. The small-signal tubes, for voltage gain and phase inversion, are a single 12SJ7 and a pair of 12SN7s, while all rectification is solid-state. But like some of the best power amplifiers around, that sonic character is exceptionally limited. For his Follow-Up, JA auditioned the Bricasti amps in his own system, and described the sonic balance achieved by the combination of Bricasti amps and KEF Blade Two loudspeakers as being "a little on the polite side." This What Fi-Fi Award-winner is our MVP, and one of the best stereo amps you can buy for around $1000. “Astounding speed and explosiveness,” is what you get from this KT-150 beast, along with a new design that maximizes tube life. Mikey added that "the Hyperion strikes the ideal balance between tube-amp richness and flow and solid-state quiet, authority, and dynamic swagger," and proclaimed it "among . An advanced version of that innovation, the Double Diamond output stage, along with Ayre's recently developed AyreLock voltage-regulator refinement, and a few other new refinements, have now been applied to Ayre's top-of-the-line power amplifier. The BasX A-100 stereo integrated amp is built like no other amp I've ever seen for its price of $229 (£299 or about AU$520). (Vol.39 No.11 WWW). One effect of the feature is to flesh out the three-dimensionality of instrumental images. Both single-ended (RCA) and balanced (XLR) inputs are provided. Speakers of 96dB+ sensitivity are advisable. For those who might be intimidated by the idea of tubes, VTL has made the ST-150’s manual bias-adjustment fairly straightforward. (Vol.41 No.7 WWW), Doshi Monoblock V3.0: $35,995/pair LG's conclusion: "My last impression of the Prometheus was the same as my first: It's one of the best-sounding amplifiers I've heard in my listening room." Output power is specified as 370W into 8 ohms, with the first 100W assured as being in class-A, and 650W into 4 ohms. Especially when combined with the classic Rogers LS3/5a, JA observed "superb imaging definition and stability" with the good-looking MBL amps. . The JL Audio JX1000 is the best monoblock amplifier on the market that provides excellent performance and relatively good value for money. Luscious, velvety, silken, gorgeous, it’s the kind of sound around which audio cults develop, and it’s easy to imagine its owners years, even decades hence treasuring the Bia the way others do classic McIntoshes and Marantzes. Having heard this speaker live, I don't hear what they hear. Its top end, where Class D has previously struggled, is smooth and extended, not glassy. [with] pure, not-unexpected single-ended magic." He also noted that "The Prometheuses projected a broad, detailed, involving, three-dimensional soundstage," and "the midrange response blossomed when my [Quad ESL-989] speakers were driven by the Thetas." (Vol.40 No.10 WWW), Lamm Industries M1.2 Reference monoblock: $32,490/pair ★ Writing from his lab, JA noted that the AkitikA "is happier driving higher impedances, though this drawback must be considered in the context of its very affordable price." The colossal gain of the original has been reduced to a reasonable sensitivity of 0.8V. There are virtually no tonal imbalances, rhythmic lagging, slurred transients, dynamic compression, image flattening, distortion, or strain. 1) Rockport Technologies Avior II Is there any difference between Macintosh V. VI and LE? (The latter represents a confusing bit of nomenclature: a fixed-bias amp is one whose bias voltage requires periodic adjustment.) The Stellar M1200 monoblock amps are rated at 1200 watts into 4ohms and 600 watts into 8ohms. Its MOSFET output stage draws from separate power supplies for its positive and negative swingsthere are also separate mains-transformer windings for positive and negative voltagesand outputs 400W into 8 ohms, 700W into 4 ohms, or 1100W into 2 ohms. Compared to its predecessor, the Limited Edition version of McIntosh's MC275 ($6500) has beefier binding posts, a more conveniently positioned power switch, and a gold-plated rather than stainless-steel chassis. . Their latest amp, the 25Wpc J2, impressed HR with its "grainless images and head-shaking rhythms. HR tried the Pass with a great variety of speakers, starting with a rebuilt pair of original Quad ESL electrostatics: "Through the Quads, the XA25 radically improved the tactile presence of music and musicians, their voices and instruments," he wrote. Alpine is the name that needs no introduction for those who have been a part of the audiophile army long enough. His verdict: "reasonably priced, strong beyond its power rating, and positively revelatory." I expect better than jut a rehash of the 2018 recommended components. The J2 didn't have quite the vividness of Herb's tubed Line Magnetic LM-518IA, but made up for it with its dependable musicality: "Every day, [the First Watt J2] made me and my favorite loudspeakers extremely happy. In the Moon's case (haw), much of that weight comes from the massive, elaborate, one-piece aluminum castings that comprise the amp's side panels, each one enfolding, damping, and heatsinking the 32 output transistors per channel. The amplifiers belie their rated power, and drive low-efficiency loudspeakers with ease. Like earlier models, the latest Haut-Brion uses two matched pairs of the rare 6L6GAY pentode tube to deliver 20Wpc. (Vol.41 No.8 WWW), PS Audio BHK Signature 300 monoblock: $14,998/pair ★ The 350Wpc, class-AB No.534 stereo amp can be seen as a less expensive alternative to Mark Levinson's 400W No.536 monoblock (see below). This 300W (into 8 ohms) hybrid (tube input stage/MOSFET output stage) monoblock is the distillation of all that celebrated electronics designer Bascom H. King has learned about amplifier circuits. (Vol.41 No.10 WWW), BorderPatrol P21 EXD: $14,450 with 300B tubes The BorderPatrol P21 EXD is a 300B amp with a twist: although its present-day reputation stems from its appearance in single-ended amplifiers, here the hallowed 300B output tube is used in pairs, for push-pull operation, producing what designer Gary Dews claims to be an output of 20Wpc. That takes big heatsinks and a good deal of design cunning, and the XA200.8 shows evidence of both, the latter in its DC-coupled front end and distinctive application of input-stage feedback, the former in its . This 60Wpc stereo amp also proved to be more versatile than expected, driving a remarkable array of loudspeakers to great effect. that we could hope for in a 21st-century tube amp." * Thor monoblock amps. And with Tidal's mighty Akira speakers, the Constellation offered "superb" dynamics: "The timpani blows . Each Moon 888 also includes two massive, potted power transformers, 12 big, custom-made power-supply storage capacitors, and a cast-aluminum chassis capable of supporting all of the above. The Michi P5 Control Amplifier ($4K), S5 Stereo Amplifier ($7K), and M8 Monoblock Amplifier ($7K) are Rotel’s new flagship audio offerings, promising superb build quality, elegant design, and unshakeable 2CH performance. Writing from his test bench, JA concluded that the PrimaLuna "measures about as well as can be expected from a classic tube design that uses a push-pull pair of [EL34s]," but cautioned against using it with lower-impedance speakers. He bought the review sample. The output tubes are a single 300B per channel, specified to output 9W each. This fully balanced, Class AB amplifier packs 600 watts (8 ohms) into a normal-sized, 42-pound single chassis per channel. The resuscitation of Audio Alchemy brings with it a new line of relatively affordable electronicsincluding the Peter Madnickdesigned DPA-1M monoblock. With the MQ-88uSE driving his DeVore Orangutan O/93 speakers, AD reported superb musicalityexcellent musical momentum, flow, and pacingand a sense of touch by which "every [harp] arpeggio was a tactile delight." Surprisingly, the Inspiration’s bass may even be deeper and more powerful than that of the original Hercules. Reporting from his test bench, JA noted the amp's significantly-lower-than-specified input impedance but also its slightly-higher-than-specified (550Wpc) power into 8 ohms. JVS also discovered the Progression Monoblocks' fine performance: "Not only did [they] nail the savagery of the high-driving piccolos and brutal bass without breaking a sweat, they also kept every instrument in control and balance while conveying a realistic, airy soundstage." And the list goes on and on and on. It shone brightly every time with a golden sense of bloom, inviting detail, and unwavering musicality.