Integrated Amp Reviews

I could be persnickety about some extra thickness and roundness of sound, but for what purpose? Even with some added thickness, Jimmy sounded a lot like he would have on a jukebox in 1962 when this recording first appeared: big and solid with plenty of twang and reverb. More than usual, I enjoyed all the tracks on this album.

With the Magnepan .7
I knew in advance that the Magnepan .7 quasi-ribbon panel speakers plus Quad Artera Solus would be a happy marriage. I felt certain that the Quad's class-AB amp would dump enough current into the Maggie's 4 ohm load. And it did. I liked how the Artera Solus gave weight to instruments like Boubacar Traoré's electric guitar on his 1990 debut album Mariama (44.1/16 FLAC Syllart Records/Qobuz). The ebb and flow of Boubacar's guitar-reverb was enjoyably tangible. I dug this amp-speaker combo so much that, while using the Quad's built-in DAC, I switched from the default Smooth to the Fast filter so that I could revel in the nuance, tone, and melancholy rhythms of this magical meeting of the Niger and Mississippi rivers. Imagine beautifully sung, danceable blues constructed over ancient African rhythms. Streaming Mariama through the Magnepan .7 loudspeakers, the Artera Solus allowed me to bask in pleasurable sonics and memories of Africa while enjoying the soul of the performance.

I ask you, is there a higher high than Miles Davis's Live-Evil? If there is, I have not yet experienced it. Using the HoloAudio Spring DAC via a line-level input, I listened to the album's hallucinatory fourth track, "What I Say" (44.1/16 FLAC Columbia/Tidal), during which the Quad integrated amp allowed the Magnepans to sort out dense masses of notes and fusing rhythms. Jack DeJohnette's drumming was creative beyond my wildest dreams. Plus, his drums sounded unusually three-dimensional: more solid and sonically expansive than usual. I have never admired Keith Jarrett more than I did on "What I Say": He lets it all out. This type of intense music is exactly what the modest Maggies do best. The Artera Solus made Live-Evil into a memorable audio moment. An excellent amp-speaker combo.

Compared to the Pass Labs INT-25
My solid-state reference integrated amp is the Pass Labs INT-25. I call the INT-25 a "featureless" integrated because it is only a power amplifier with a minimalist single-ended line stage. It weighs twice as much (50lb), has one-third the power, and costs three times as much ($7250) as the Quad Artera Solus. The INT-25 does not include a DAC, a headphone amp, an iPhone app, or a CD player. The INT-25 makes only 25 class-A watts per channel (at 8 ohms), vs the Solus's 75 class-AB watts. I wanted to compare these two to see how close the Artera Solus —the amp and preamp only, with external DAC feeding the line inputs —came to sounding like a state-of-the-art solid-state amplifier.

The Pass Labs integrated let me hear Julius Katchen's performance of Beethoven's final piano sonata (Op.111) as a pure emanation of spirit, fierce and majestic. Katchen is known best for his fiery Brahms recitals, but I have not yet grasped Brahms's art in the same way that I get Beethoven's poetic Op.111 Sonata, from Julius Katchen: Decca Recordings 1949–1968 (44.1/16 FLAC Decca/Tidal). With the INT-25 driving the Magnepan .7s, this Decca recording presented itself as highly resolved and weighty, and as a grand expression of poetic Art. Notes and chords emerged from a tangibly present soundboard, and I was often aware of the piano's interior volume. With the INT-25, the piano's natural reverberation was abundant and sensuous. The INT-25's almost grainless resolution was not the least bit hard—or soft.

With the Quad Artera Solus, Beethoven's Op.111 was gutsy and powerful. The music's emotional tensions were easy to observe. Katchen's keyboard mastery was delivered with fierce momentum. But, compared to the INT-25, every note sounded slightly blunted. Reverberation was almost entirely missing. Atmosphere, pulsing air, instrumental textures, and transparency were reduced, as were nuance and brilliance. The Quad played this Beethoven earnestly and robustly. The Pass Labs made it subtle and sublime.

Playing CDs
With the Artera Solus, every source and every loudspeaker presented itself with dynamic force and an ardent musicality. However, as this review progressed, I began to see how the CD player might be not just an add-on feature but the Artera Solus's raison d'eêtre.

I was so against integrated amps with "features" that it took me some time to grasp how incredibly well the Solus's CD player parlayed the aforementioned force and musicality into a form of vivid potency, the likes of which I can't recall experiencing from a CD player. The Artera Solus CD player made each individual CD, and every genre of music, sound unique and exposed in ways that complemented the artist and record producer's intent.

One recording tells the whole story: Volume 5 of Rounder Records' Southern Journey Series of Alan Lomax recordings, Bad Man Ballads: Songs of Outlaws and Desperadoes (Rounder CD 1705). Lomax recorded mostly rural and mostly uncelebrated performers using a single mono or stereo microphone in a single, ordinary room. He would simply turn on his recorder and capture unedited takes. Pure and direct, with supertransparency.

The first thing I noticed on Bad Man Ballads was some slight veiling compared to my Integra DPS-7.2 (used as a transport) driving either the Chord Qutest or HoloAudio Spring DACs. However! The ancient Integra played rhythms like limp celery compared to the fierce punch, drive, and in-the-room solidity demonstrated by the Quad's CD player.

In my house, streaming usually sounds better than CD—but not with the Artera Solus, which made CDs superior to all other digital sources.

Listening via Bluetooth
The Quad offers Bluetooth—the basic A2DP and QualComm's superior aptX. Used with my iPhone, however, only the garden-variety A2DP was available, since the iPhone doesn't support aptX.

Sourcing the Artera Solus via Bluetooth was easy. I installed the Foobar2000 iPhone app and, 20 seconds later, I was listening to Ali Akbar Khan's Peerless (44.1/16 FLAC, Navras/Tidal) on my iPhone 8. With the Klipsch RP-600Ms, the sound was good, but not nearly as good as from the Artera Solus's CD player, or streaming via its USB input. Via Bluetooth, the Artera Solus sounded relatively clean (for Bluetooth) and lively, but dull.

Headphone output
When I review integrated amplifiers with headphone amps, I try to challenge them on the first try. This time I used the uber-transparent but notoriously difficult to drive (50 ohms, 83.5dB/mW) HiFiMan HE6se headphones. To play loud, these headphones need more voltage and current than most other headphones. With the HE6se 'phones, the Artera Solus generated relaxed, moderately detailed, but dull and flat sound. Not surprisingly, with this load the Quad's headphone output was gain-challenged and could deliver only modest sound-pressure levels. Not a good match.

After trying an assortment of popular headphones by Grado, Audeze, and AudioQuest, with mediocre results, I resorted to my current favorite daily-driver headphones: the Focal Clears. The Clears are extremely easy to drive (55 ohms, 104dB SPL/1mW) and have superb pitch definition. They are naturally detailed and virtually fatigue-free, both sonically and physically (ie, on my head).

To my surprise, the Focal Clears sounded rather enchanting playing the above-mentioned Carmen Fantaisie and the Beethoven piano sonata. For some reason, with the Clears, music did not sound dull or distant —just lacking in energy and detail at the frequency extremes.

The Quad's headphone output is fine for easy loads, but I cannot recommend it to serious headphone enthusiasts.

In sum
As I mentioned earlier, audio components usually fall into one of three categories: boring, annoying, or engaging. Quad's Artera Solus fell easily into the third category. It was exciting to use, and it delivered music with a uniquely satisfying je ne sais quoi that I can best describe as sounding strong and musical. Recommended for the music-first audiophile who still enjoys CDs, and who wants lively, natural sound from a simple system.