Integrated Amp Reviews

I've been to a few bowling parties and passed a bottle around a few fire pits, but I've never watched an audiophile unboxing video. Lately though, I have been paying closer attention to my first impressions of each new audio product as it enters my realm.

I'm finding it interesting to notice how a device previously unseen and unheard declares itself one small step at a time as I open its box, feel its heft, observe its form, study its manual, and, finally, wire it into my system. Those start-up experiences, plus my gut feelings during my first moments of music listening, establish a tone of innocent discovery I wish would last the whole month. It never does.

I mention this because my first impressions for my first-ever review of an ARCAM product, the Radia A25 integrated amplifier, were in that "innocent and receptive" mode from the instant I saw the box sitting outside my door. The 26.5lb box looked Jimmy Stewart–trim and reasonably sized (8" × 23" × 17"), and it was easy to lift. My first impression was that ARCAM had their box and packing game together.

The first tell was the brown paper tape, which, with three quick box-cutter cuts, revealed an inner "tuck top" box with a giant letter "A" printed on its cover, formed from thin black lines suggesting piano keys. This tuck-topped box opened to reveal a brown, cast-paper eggcrate-type spacer with a small brown cardboard box nested in its center. That small box contained a sharp-looking (plastic) remote and an IEC power cord. The A25's nine-language quick-start guide was in a brown paper envelope affixed with brown tape to the inside of the top cover. The A25 itself was sheathed in a white paper-cloth bag.

This was my first-ever encounter with smartly engineered, artfully executed, 100% biodegradable packaging, and it felt like a sincere handshake.

ARCAM
Back in the day, in Great Britain, Amplification & Recording Cambridge Ltd., t/a ARCAM, made slim-profiled integrated amplifiers reputed to work well with England's most popular speaker: the Wharfedale Diamond shelf-mount. That's all I knew about ARCAM before I started writing this report (footnote 1).

ARCAM's website says "The 'A' in ARCAM stands for Amplification—this is our core competence. The A25 is the latest in more than 45 years of amplifier design and manufacture, going back to our first product in 1976—the A&R Cambridge A60 amplifier."

Description
ARCAM's flagship Radia A25 is a slender, nicely sculpted, matte-black, 19.8lb integrated amplifier that operates in class-G and is specified to output 100Wpc into 8 ohms and 165Wpc into 4 ohms.

The A25 is designed in Cambridge, UK, and built in China. Its back panel features stereo pairs of loudspeaker binding posts plus three unbalanced RCA inputs and one RCA input for a moving magnet phono cartridge. There are also four digital inputs: two coaxial, one optical, and one USB-C. The A25's DAC uses an ESS Sabre ES9280A Pro DAC chip, which allows a choice of three reconstruction filters and supports PCM sampling rates up to 384kHz and DSD up to DSD1024. There is also a variable (volume-controlled) pre-out on RCA, 12V triggers In and Out (also on RCA), an IR sensor input, and Control input over a LAN (RJ45) connection, and a USB Service port. The 19.8lb chassis measures a slim 3.27" high, 17" wide, and 13.5" deep including those binding posts. Bluetooth—specifically several flavors of aptX including aptX Adaptive, Apple's AAC, and the baseline SBC—is also featured. The A25's Bluetooth is two-way: It can receive music data from a phone or tablet or send it out to a pair of wireless headphones.

The A25's "buttonless" front panel looks smartly styled by day and extraordinarily nice in the dark, where thin, creamy-yellow bands of light halo the Volume and Input Selector dials. Its slender LCD display is just the right size—and brightness-adjustable—to feel polite and subdued yet perfectly legible from 10' away. Its 6" × 1.5" × 0.5" plastic remote looked expensive and felt right in my hand.

The A25's 3.5mm headphone jack hides in the amp's lower left front corner. Opposite top right is a tiny white LED that lights bright when the unit is fully powered and becomes dimmer when it goes into standby.

In use, the A25's subtly styled gray-black chassis came off as uptown bureau-top ready, like a product that should cost a lot more than its $1499 price.

Listening with Heretic AD614s
I began my listening with the ARCAM A25 powering the Heretic AD614 speakers and a Roon-streamed digital remastering of one of my all-time most-played LPs (Columbia LP ML 4587): the Budapest String Quartet performing Beethoven's sublimely formed Grosse Fuge in B-Flat Major, Op.133.

The original 1953 Columbia mono disc produced an exceptionally dense, life-like sound that intensified the effect of the Budapest String Quartet in delivering this soul-stirring performance. That old black disc is gone, but the hi-rez remastering (24/192 FLAC, Columbia/Qobuz), played through the Denafrips Terminator Plus DAC into the A25's analog input, made exceedingly smooth, instantly engaging sound laced with tone that was more saturated and tempo-keeping that was more toe-tapping than expected. Playing Op.133, the ARCAM exceled at sorting all the sound molecules and not mucking them up. It felt good to hear a $1499 integrated amp make a piece of difficult music this affecting. Its natural ease invited me to lean forward and close my eyes.

Right now, my system is silent, but as I type these words, I can still hear Op.133 playing inside my head. I keep trying to imagine what was going on inside of Beethoven's head as he composed these dark, quivering forms. Driving the Heretic speakers, the A25 presented the Maestro's Grosse Fuge as a daring artistic invention performed by a brilliant quartet operating in peak form.

Driving LS3/5a's
The first thing I noticed when I switched from the 97dB-sensitive Heretic AD614 speakers to the 83dB-sensitive Falcon Gold Badge LS3/5a's is how much I had to turn the volume up; 14dB is a lot of gain to lose and make up for. The second thing I noticed is how little room air the Falcons move in comparison to the Heretics.

Besides moving less air, the chief sonic difference between the Heretic and Falcon speakers is how the sealed-box Falcons place performers farther back and spread them out more. The other sonic difference is a consequence of the first: With the A25 driving the LS3/5a's, the Budapest String Quartet's performance of Beethoven's Op.133 seemed less raw, real, close-up, and direct than it did with the Heretics. Less edgy, more compressed, more pipe'n'slippers British.

The greatest weakness of this amp-speaker pairing was its lack of punch or sparkly zing. Bass was tight, tuneful, and well-managed but more prosaic than visceral. The A25 + LS3/5a combo's greatest strength was how explicitly it invited close listening while never being boring or fatiguing.

Driving headphones
Once again, the ARCAM Radia A25 made a brilliant first impression. Its single 3.5mm headphone output powered Grado's $295 Prestige SR325X dynamic headphones like it was designed specifically for the task. I'm reading Robert "Mack" McCormick's Biography of a Phantom (Smithsonian Books), so my mind is wandering Friars Point, Mississippi, looking for Robert Johnson's sassy girlfriend "Betty," who's "got a mortgage on my body and a lien on my soul," while playing Columbia's paradigm-shifting 1961 LP, King of the Delta Blues Singers (16/44.1 FLAC Columbia/Qobuz). This recording did not sell many copies, but every rock and blues musician of the 1960s was impacted by it. Powered by the A25, the 32 ohm, 98dB/mW SR325Xs exposed all the darkness and vibrant energy of Johnson's spooky poetry. The Phantom's haunting voice and stupefying guitar accompaniments came through these Grados with all their sharecropper-minstrel mojo intact.

The A25 manual says the A25's headphone output will drive headphones between 16 and 2k ohms, delivering 2.5V into 32 ohms, and 5V into 300 ohms. Naturally I had to try my 250 ohm Beyerdynamic DT 880 Pro headset. I played "Cross Road Blues" at a loud volume, and the 880s played studio-monitor clean but a little darker and slower than Grado's bright-and-awake, low-impedance SR325Xs.

Meze Audio's $795 109 Pro dynamic headphones (see Gramophone Dreams elsewhere in this issue) is my current favorite headphone for everyday all-genre use. The 109 Pro is beautifully crafted and exquisitely balanced tone-wise. Like ARCAM's A25, the sound is predominantly smooth and mesmerizing, precisely how they sounded playing Ito Ema's performance of Bach's Goldberg Variations on a Steinway & Sons Model D piano (M•A Recordings CD M024A). With the 40 ohm, 112dB/mW Meze 109 Pros, powered by the A25's headphone amplifier, the sound was akin to perfect: creamy textured, easy-flowing, precise, and pure of tone. Never had this Bach seemed dreamier or more exciting to follow. A divine pairing.

Apparently the "A" in ARCAM does stand for Amplification, and this headphone amplifier achieved an A+ for amplification excellence.

Bluetooth
The A25 gave me an excuse to see how good Bluetooth is sounding these days. The answer: better—but still not audiophile quality. What I heard streaming Tidal and YouTube from my iPhone 11 sounded moderately purer and more spatially descriptive (footnote 2).

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Footnote 1: For what it's worth, an ARCAM integrated—I don't recall which model—was one of my earliest audiophile purchases, not counting the stuff I bought in my youth. I was happy with it for a while, with my Vienna Acoustics Bach loudspeakers, but I had been bitten by the bug and the rest is, if not history, then reasonably well-known.—Jim Austin

Footnote 2: It is important to mention here that because the iPhone doesn't support AptX Adaptive (or any AptX Bluetooth), it's unlikely I heard the ARCAM's Bluetooth at its best. If you intend to use Bluetooth—and if optimal quality on Bluetooth is important to you—make sure the sending device supports this AptX codec.