Integrated Amp Reviews

Compared to Rogue Audio Sphinx
Rogue Audio's tube/class-D hybrid Sphinx V3 and Musical Fidelity's A1 sounded more alike than different. Still, the "different" part was important.

The Sphinx V3 uses an N-core power module to make 100 class-D watts into 8 ohms. It costs $1595 and has a killer, to-die-for MM/ MC phono stage that came across as more transparent than the A1's. As always when comparing components, the sound character of the previous component affects what I notice first with the new component that replaces it.

In this case, I'd been listening to pianist Raymond Lewenthal playing and conducting Funeral March for a Papagallo (Columbia LP M30234), composed by my favorite recluse-visionary savant, Charles-Valentin Alkan (1813–1888). This is strange, edgy art music that is challenging to execute. Raymond Lewenthal specializes in performing Alkan's works, and his talent and passion for the composer brings this fine-sounding recording to life—and to blood-squirting life it came with the Nagaoka MP-200 driving first the A1's MM stage, then the Sphinx V3's.

What I'm comparing here are two of the most refined, rich, human-sounding phono stages ever included in a humbly priced integrated. These are "never need better" phono stages embedded in amplifiers designed to satisfy over the long haul. But as I played Lewenthal's Alkan and everything else I threw at it, the V3 was distinctly more transparent than the A1. The V3 sorted out the MP-200 better than the A1 did and made it sound more fleet of foot. But that didn't make the V3 more musically captivating than the A1, which maintained this weird knack for dragging me in and holding my attention better than any integrated amplifier I can remember using. Our world is blessed by gear like this.

Compared to Pass Labs INT-25
This was an easy comparison because the $8100 Pass Labs INT-25 plays my speakers like the purest bottled oxygen, and the $1779 A1 plays them like pure oxygen laced with nitrous oxide.

Sounds from the A1 are not as crisp and clean as from the famously transparent Pass Labs INT-25. Musical Fidelity's A1 is not as detailed or clear in the top two octaves. Nor is it as starched, polished, and controlled in the bottom three octaves—but oh my, save me from the Devil, the A1 has that supersaturated toaster-glowing "electrostatic midrange" that I've worshipped since I bought my Koss ESP/950 electrostatic headphone system and discovered its glowing, stereoscopic midrange. With the A1, recordings presented like View-Master slides (footnote 1), with deep, conspicuously dimensional space and supersaturated color. The INT-25 mapped the location of sounds with laser-scanner precision, but color was less saturated.

It is interesting to note that the 25W Musical Fidelity A1 played the 83dB-sensitive, 15 ohm Falcon LS3/5a and the 93dB-sensitive DeVore Fidelity O/93 with an equal sense of limitless, strain-free headroom. The A1 never slumped, strained, or became unfocused—not even playing densely layered synth or symphony orchestra music. With the A1, the DeVores played bolder but darker than they do with my Elekit TU-8900 or my Parasound A 21+.

The 10dB drop in sensitivity when switching from the DeVores to the Falcons necessitated moving the normal listening position of the volume potentiometer two hours forward from 8 to 10 o'clock. This reminded me of the A1's gain selector button. Which I then decided to try.

With the low-sensitivity Falcons, when I switched from Normal to Direct mode, my normal listening volumes began happening with the potentiometer set in the more ideal (for a log pot) 11am– 1pm range. In Direct, there was a change in sound character, but it was not dramatic. Beethoven's String Quartet No.7 in F Major, Op.59, No.1, "Razumovsky," played by the Budapest String Quartet (24/192 FLAC Columbia/Qobuz), came across as more textural and tactile and possibly more transparent—but also less gain-fired bold than it sounded in Normal. The difference was subtle at first, but the longer I listened in Direct Mode, the brisker, cleaner, and more enticing it seemed.

Powering the Klipsch RP-600M II
Even in the A1's lower gain mode, I had to keep the volume pot dial at around 10 o'clock to compensate for the greater (94.5dB/2.83V/m) sensitivity of my beloved Klipsch RP-600M II loudspeakers ($499/pair on Amazon). But damn me to the cold earth if this system didn't play the abovementioned Beethoven quartet with more verve, top-octave energy, and low-octave vigor than my LS3/5a's did. The A1 + 600M was an instant smash hit. Through the RP-600s, this remastered 1950s recording displayed a conspicuous sense of jump beat and momentum. Instrumental textures were brighter and less dense than they were with the Falcons, but the push, clarity, and speed of the RP-600M's lower octaves (50–300Hz) distracted me from that lessening.

The main virtue of these almost-free Klipsch standmounts is their microdetail and wide-awake liveliness, not compromised by low-powered amplification. With 300Bs, their clarity and beauty are legend. With Musical Fidelity's A1, their punch and glamor were compelling.

This amp-speaker combo cost $2300 plus cables—just add a source and speaker stands. So I thought I'd replace the TEAC $2700 VRDS-700T transport and Denafrips $6400 Terminator Plus DAC with my newly beloved Onkyo C-7030 CD player ($250 on Amazon). This resulted in a modest loss of resolution and drive, but it also produced a complete, audiophile-quality sound system that cost around $3000, with $349/pair Klipsch-branded speaker stands and the AudioQuest Type 4 (approximately $220/2m) speaker wires I used to make this comparison.

Playing Monk's Dream (Columbia CD CS8765), the first thing I noticed with the Denafrips-Onkyo system was a moderate loss of information at the front and back ends of piano notes. Transients and reverb tails were mildly curtailed, but the sound was still rich and vital, with a level of tone and tempo truthfulness that revealed the invention and preserved the joyful spirit of Monk's melodies. The bass end of his keyboard had "chunk and touch," as Art Dudley used to say. The tinkly treble keys were slightly muted, but everything I needed to understand Monk's art came through in an exceedingly natural, undigital, unmechanical, nontransistory way. This high-value music system lets people who wear cargo shorts and mow their own lawns feel like they're dressed in white linen, sipping Mezcal on a beachfront veranda in Malibu (footnote 2).

Driving the GoldenEar BRX
The sensitivity of GoldenEar's $1599/pair BRX standmount loudspeakers is specified as 90dB/W/m. They play quieter and more refined than $499/pair RP-600M IIs. Their tweeter is a high-value asset that helps them play taut and sweet. But despite their highish sensitivity, the BRXes are tough to drive because, as John Atkinson put it in his BRX measurements, "The BRX has minimum EPDRs of 2.15 ohms at 59Hz and 1.53 ohms at 135Hz, and the EPDR remains below 4 ohms in the midrange."

In my room, the BRX played loud (90dB average at 2m), bell-clear, and liquid-smooth with no noticeable strain while powered by A1's 25W class-A into 8 ohms. There's no 4 ohm power spec on MF's website—nor is there a spec for total output power into 8 ohms—but the BRX never felt underpowered.

Not surprisingly, my $3599 Parasound Halo A 21+ stereo amp (500Wpc into 4 ohms) played those thick-impedance GoldenEars with more transparency, sharper-focused detail, and more precisely mapped soundspaces than the A1. But it did not outpunch, outboogie, or make better tone than the A1.

Pre Out to the Pass Labs SIT-4
In this month's Gramophone Dream (p.21), I describe my experiences with First Watt's new SIT-4, which uses new, industrial-grade "SIT" output transistors. I couldn't stop myself from checking out the flavor achieved by pairing Tim de Paravicini's line and phono stage to Nelson Pass's latest no-feedback, low-power (10W into 8 ohms) amplifier.

The SIT-4 costs $5000, and I was relishing its effect on my LS3/5as fed by HoloAudio's $3098 Serene KTE preamplifier. I was curious whether the A1's Pre Out would be as uncolored and transparent as the Serene's, which I regard as state-of-the-art invisible. And by golly it almost was. It was at least 90% as transparent as the Serene.

This arrangement also let me compare the A1's power-amp section to the SIT-4. Powered by the A1-pre/SIT-4 combo, the Falcons presented bolder, cleaner, more liquid, tactile, and exciting than they did powered by the A1 integrated—its preamp stage and output stage. This suggests that the A1's signature boldness and tactility are spawned largely in the preamp section, which appears to be a world-class component in its own right.

Conclusion
More than most amps I'm familiar with, the Musical Fidelity A1 integrated amplifier engages my brain's right and left hemispheres in roughly equal fashion. That's its chief virtue. And that is something very few amps at any price can do.

A timeless classic, as good as it was, but better.

Footnote 2: Reading through this review one last time prior to submitting it for layout, it occurred to me that, although they could afford much better, chances are that, regrettably, those mezcal-sipping Malibu folks have a music system that's vastly inferior to the one Herb was listening to.—Jim Austin