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NAGRA Pyramid Monoblock Amplifiers Review

Constantine Soo experiences the sound of Swiss engineering: a $10,995 pair of NAGRA's Pyramid Monoblock Amplifiers

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NAGRA Pyramid Monoblock Amplifiers

A worldwide leader in the creation and development of state-of-the-art broadcast systems and protocols, Nagra’s 650-million-dollar, technology-driven parent company, the Kudelski Group, employs a certain cache of insane scientists, and it is only a matter of time that the company’s think tank would find application of its technologies in home audio. Spawned from such creativity is the $11k-pair of the Nagra Pyramid Monoblock Amplifier, the subject of this review.

Nagra’s solid-state PMA owes its origin to the Swiss conglomerate’s first high-end power amplification design, the $19k Vacuum Power Amplifier. Aside from the fact that the VPA is the company’s vacuum-tube reference utilizing a push-pull pair of 845, an output tube favored by a legion of audiophiles for its well-documented conduciveness in audio reproduction, the 50Wpc non-feedback design remains a most uncommon amplifier to this day not only for the wealth of technologies it is incorporated, but also for the incomparable level of production design so readily visible.

After the VPA, the tireless Nagra engineers proceeded to create a solid-state equivalent of the reference amplifier with comparable sonics, and the now-discontinued, $16k MOSFET Power Amplifier soon became a reality, capable of delivering 250Wpc into 8Ω and 500 watts in bridged mode.

A central technology to the discontinued MPA is the patented Nagra Power Factor Corrector power supply, a highly specialized configuration of AC/DC conversion that, per Nagra, is immune to the ubiquitous but potentially hazardous AC/DC conversion practice based on transformers and capacitors.

Replacing a myriad of capacitors, the MPA’s PFC module works in tandem with a toroidal transformer of gargantuan proportions, isolating the amplifier from the electric noises generated by other electronics in the household, and stabilizing the incoming power into orderly sinusoidal current that is devoid of noises and spikes. Equally noteworthy on the PFC’s contribution is its supposedly reservoir-like properties that delivers immense, instantaneous currents when demanded by the amplifier, as well as the resultant facilitation of a more compact chassis from the reduction of downstream filtration devices.

This PFC module is now incorporated into Nagra’s 2nd-generation power amplification design, the Pyramid Monoblock Amplifier, which is also equipped with a considerably more substantial transformer.

In the years after the launch of the MPA, Nagra also began investigating the advent of switching power supply in Europe, a technology developed in anticipation of a year-2000 CE requirement, which outlined a new regulation that required all electronics to be capable of certain efficiency. Nagra’s audiophile-grade switching-mode power supply technology was thus created.

The superior operational efficiency as accorded by the Nagra switching-mode power supply, plus the company’s own Power Factor Corrector technology, created a remarkable technological convergence that enabled the engineers finally to utilize only two meticulously-matched Exicon MOSFETs to produce a monoblock amplifier capable of delivering some 200Wpc into an 8Ω load, as well as a current delivery very close to that of the MPA, and yet priced at a lower MSRP of $10,995 per pair.

Nagra’s engineers then proceeded to create a platform for highlighting such technological marvel. Utilizing the pyramid geometry, Nagra’s engineers created a base cast from a solid piece of aluminum of such sheer mass that provided superb mechanical stability, at the same time incorporating a 50° angle of incident on four sides of the pyramid to function doubly as an optimal heatsink for the transistors.

The PMA is also equipped with a robust monitoring circuit that disconnects the amplifier from the loudspeaker either when the operating temperature rises in excess of 140°F or when there is a DC fluctuation in excess of +/- 2.5 volts.

Upon powering on, a toggle switch on the PMA’s rear panel serves as a secondary activation stage with the settings of ON, AUTO and OFF. Besides the ON setting, AUTO puts the amplifier into standby mode after 15 minutes of idling, and springs the amplifier back into action again upon signal detection. Because I am liable to engage in phone conversations at anytime during a weekday, I left the PMA’s in the AUTO mode until I go to bed. During the weekend or holidays when my wife and her schedules of “beauty sleep” allowed me to listen on for hours, I switched the unit from OFF, and then past the AUTO, to ON.

Also on the rear panel is a set of vertically positioned LED’s labeled from bottom to top as ON, OVERHEAT, ERROR, the last of which would put the Pyramid into protection mode whenever there is the presence of clipping, shortcut or DC problem. Finally, a user-adjustable jumper switch for activating either the XLR or the RCA input is also on the back panel.

A switchable blue and red LED is fitted through two tiny slots on the front of the pyramid at lower right. When set to active display, the blue LED tracks the Pyramid’s output strength with varying brightness, engaging the red LED simultaneously during a peak current of 12 amperes or more. The Pyramid’s Operating Manual suggests volume reduction to dim the red LED, thus avoiding clipping.

Speaker binding posts incorporated into the PMA’s are the WBT gold-plated type, proportioned to accept either a 4mm banana plug, a 6.35mm spade lug, or a 4.2mm bare wire.

Nagra’s pyramid amplifier is also available in a stereo form, the Pyramid Stereo Amplifier, with half of the PMA’s power, at an MSRP of $6,595.

System Set-Up & Auditioning

47 Laboratory’s PiTracer CD transport assumed its longstanding role as my reference transport in conjunction with Wadia’s 27ix v3.0 Decoding Computer. Nagra’s own $8,995 PL-L class A tube preamplifier served as the primary preamplification, while Accuphase’s E-550 integrated amplifier also was rotated with its separable preamplification auditioned.

BNC digital cable was the Analysis-Plus Silver Oval. Two pairs of Combak’s 2-meter, $2,250 HS-101GP RCA interconnects secured connections all the way from the Wadia to the PMA’s. A 2.5-meter run of the company’s matching, $3,100 HS-101 SLC “Sophisticated Listener’s Choice” speaker cables served as the single-wired cable with either the $25k Bösendorfer VC 7 speakers or the $12.5k MaxxHorn Immersion horn speakers. A 5-foot run of Audio Note’s Sogon™ speaker cables in bi-wired drove the $19k Tannoy Churchill Wideband loudspeakers.

Each Pyramid Monoblock Amplifier was isolated from the carpeted floor by four downward-pointing Combak Harmonix TU-220MT Mega-Tone Tiptoes.

In the company of Nagra’s own PL-L tube preamplifier, the $11k Pyramid’s interaction with the $25k, 3-way 6-driver, 91dB/4Ω Bösendorfer VC 7 speakers displayed the monoblock’s superior channel separation in exploitation of the Austrian speakers’ potentials. In reproducing Classical pianist Evgeny Kissin’s 20-bit RCA recordings, the Pyramid’s exerted an unprecedented abundance of acoustic cues from each of the speaker’s drivers with amazing but consistent precision, creating some of the most evocative spatiality of a piano’s tones.

Vocalizations also benefited from the Nagra/Bösendorfer system’s superb spatial and tonal articulation. Although the Austrian speakers, by virtue of their benign efficiency, was able to reenact a most sonorous listening experience in a wide variety of musical forms via the 7Wpc Combak Harmonix Reimyo PAT-777 SET stereo amplifier, their dynamic envelope was pushed inconceivably by the Pyramid’s in reproducing a definitive, powerful sonority in both the female vocalist and the accompanying choir in Proprius’ Cantate Domino Redbook CD. There was a dimensionality and fullness from the Nagra/Bösendorfer system that was utterly uncharacteristic of solid-state devices.

The 104dB-sensitive MaxxHorn Immersion, capable of coming alive in my listening room with minimal power, reenacted audibly more spacious recording venues as driven by the Pyramid’s than by any other solid-state amplifications to date. Separation of instruments onstage and definition of individual instrument’s tonality from the Pyramid-driven MaxxHorn attained the most superlative ever, projecting a surreal calmness against a background of lively dialogues.

Tonality-wise, as the MaxxHorn’s recent partnership with the 211-based $79k Audio Note Ongaku provided powerful testimonial in its inherent competency, so did its pairing with the $11k Nagra monoblocks, which induced a tonal sophistication in it that though not of the Audio Note’s caliber, was nevertheless one with profound merits that would surprise many horn aficionados.

Yet, witnessing the both the 6-driver Bösendorfer and the single-driver Maxxhorn churning out their unprecedented, respective dynamic vigor as driven by the Nagra monoblocks were gratifying experiences only to be surpassed by the presence of the 15-inch Dual-Concentric™ driver of the Tannoy Churchill Wideband. For in the particular aspect of dynamic scaling, it was the Tannoy’s large-diameter driver that demonstrated the biggest strides as facilitated by the Swiss amplifiers.

The 15-inch Dual-Concentric driver’s dynamic scaling of orchestral music had always been breathtaking, but for the first time, situated slightly closer to the front wall than that in the original Dagogo Review, the Tannoy Churchill Wideband’s reproduction of Bee Gees’ “Tragedy” flooded the listening room with dynamics of incredible agility, in conjunction with a tour-de-force in supreme dynamic scaling. While the horn speakers have been vanquished by the 7Wpc Harmonix Reimyo PAT-777, the degree of dynamic scaling as treated toward this archaic disco rock music by the Tannoy signified the first time I realized how free of compression these big drivers can achieve.

Whereas the best of SETs made the most of the Tannoy’s spectral coherency and spatiality, it was the Nagra PMA’s that unleashed such colossal range of dynamics from the 95dB speakers. Hence, with the Swiss engines by my side, I began a series of pilgrimage sessions to the rock music of the 80s, taking advantage of the clean dynamics thus exerted and blasted the speakers beyond 95dB consistently. In the most particular act of reproducing the zeal in Seal’s groundbreaking rock’n roll masterpiece album of the same name, amidst the complex instrumentation was an articulate, reverberating and solid bass line that never wavered. Rock music was at its most intense under the realm of the Nagra/Tannoy system. I reckon that a good part of the Pyramid’s influence was in its exacting control of Tannoy’s 15-inch Dual-Concentric drivers.

I reckon that the Nagra’s were the first solid-state amplifiers to induce my Tannoy recklessness; for music, including the noisier ones, had never sounded so easy to the ear at 95dB+. During those sessions, I recaptured moments of my youth and understood my need for teenage rock bands to exist and flourish. I was right there banging my head in my imaginary, shoulder-length hair.

Furutech’s $980 e-TP609 AC Director played an instrumental role in facilitating a prerequisite in power purity for the Pyramid Monoblock Amplifiers to work with, particularly when the Pyramid’s were asked to amplify a miniscule input signal of normal vigor into unusually immense volumes of power. For as they drove all other speakers in my household without any incident at all times, the Pyramid’s reverted to protection mode occasionally regardless of preamplifications assigned when asked to drive the 78dB/8Ω Murata loudspeaker.

Contrasting having only the DAC plugged into the Furutech, plugging the 47 Lab, Wadia and the preamplifier altogether into the Furutech e-TP609 while having the Pyramid’s continued to draw directly from the AC outlets circumvented the predicament, while having the Pyramid’s plugged into the Furutech alone via two of Isoclean’s $2,100 Super Focus AC cables also resolved the issue, albeit an expectedly mild restraint in the dynamic envelope. At least for the 1st scenario, it would seem that by virtue of what the Furutech was designed for, it filtered out certain detrimental elements in all the DC flowing from the top all the way to the Pyramid’s that had triggered the monoblock’s protection circuits initially when driving the Murata.

The 2nd scenario, however, seemed to indicate that filtering the AC at any point in the signal’s flow would also provide the same benefit. In the Nagra PMA and Murata ES301 system, I preferred ultimately plugging upstream equipment into the Furutech and leaving the Pyramid’s to draw raw power from the AC outlets for the sheer sake of dynamics. And the results were spectacular.

In terms of power, although the Murata could be driven theoretically with a normal amplifier to realize an average listening sound pressure of around 88dB at my listening position, the ceramic-dome floorstanding speakers took on a higher dimensional of sonic prowess with the Pyramid monoblocks with definitive, pristine sonics.

During these instances, each Pyramid’s blue and red LED’s became constantly on at full brightness, and yet the music continued to proliferate. I could turn off the LEDs via a port through the bottom chassis just for the peace of mind from ignorance, which bothered my wife considerably, and try not to contemplate the level of output it could be generating; but like she said, since they were working just fine, switching off the LEDs would remove one distraction.

Conclusion

Nagra’s $11k pair of Pyramid Monoblock Amplifier, or simply the PMA, not only represents the latest statement in solid-state design by the 650-million-dollar Swiss conglomerate’s engineers, it is the milestone product in the company’s long and illustrious R&D efforts in audio engineering.

Sheer engineering brilliance permeated through every angle and performance of the Nagra Pyramid Monoblock Amplifier. From the pyramid’s 50° angle-of-incident to the multiplicity of technologies, the Nagra PMA is a powerful embodiment of engineering elegance, and a definitive statement in amplification design.

Though not given a chance in this review to demonstrate their capability of reproducing an ultra-wide frequency range of 10Hz to 70kHz with a hi-rez format, the pair of Nagra Pyramid Monoblock Amplifier nevertheless induced the most consummate performances as solid-state devices from several types of loudspeakers it was asked to drive.

Among its consummate suite of sonic attributes, the pair of Nagra amplifiers’ dynamic competence presided above all as illustrated by loudspeaker systems. Yet, during other times, it was also the tonal delicacy it could muster out of a horn and control of varying multiplicity and sizes of drivers that defined its finesse. The Nagra’s imparted a most flamboyant display of instruments’ totality in tone, such as the rare realism of a piano’s dual personality of a feathery liquidity and substantial might, so much so as to be fundamentally devoid of the rawness of many solid-state designs.

While the Combak SET has no equal in the resolution it can induced from all speakers used in this review via its WE300B’s, the Swiss twins coerced the speakers into presenting the most spectacular dynamic envelopes and frequency extensions.

But the irresistibly alluring aspects of Nagra’s Pyramid Monoblock Amplifiers spanned beyond its sonic attributes. Apart from the fact that the monoblocks signified a brilliant convergence of electronic and mechanical properties that permitted speakers to excel, their designers accomplished one of the highest forms of engineering art in endowing the amplifiers with a silvery pyramid that invokes timelessness. Nagra Pyramid Monoblock Amplifier: I dub thee “Swiss engineering that sounds as magnificent as its looks”.

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