Integrated Amp Reviews

Back when gasoline had lead in it and amplifiers came with circuit diagrams in the back of the manual, there was an unspoken understanding that power meant weight. A professional camera was a Graflex Speed Graphic or a Hasselblad 1000F, built like a small battleship and nearly as heavy. Powerful car engines were cast-iron V8s with cylinders you could stick a fist in. And of course, serious amps had transformers that could double as boat anchors.

These days, amplifier design often emphasizes efficiency. Class-D amps in particular have come a long way. Many are terrific, and they're undeniably practical. But there's still something uniquely satisfying about a design that prioritizes timeless expression over economy of electricity or space.

The Pathos InPoL Legacy, a class-A design, is unapologetically massive and so gloriously overbuilt that moving it requires a tactical plan and a chiropractor. It is the most ambitious product that Pathos has ever built—a $55,000 set-no-limits behemoth that's as much a monument to excess as an argument against half-measures. It communicates in warm, golden tones that there's still magic in thermionic emission, even (or especially) when it arrives in a 309lb (!) package.

Ciao, bella
In my review of the solid state Audia Flight FLS10 (see the February 2025 Stereophile), I nattered that an integrated amplifier "helps declutter a room, appealing to minimalists." Ha. There's nothing minimalist about the integrated Pathos InPoL Legacy. It weighs as much as an offensive lineman (footnote 1). It's 34" deep—almost three vinyl albums laid end to end. My equipment console would tolerate neither its heft nor its depth, so I relied instead on a superbly built 3'-deep, 22"-wide Pagode amp platform from German company Finite Elemente.

When the movers carried the Legacy into my listening room, lowered it on the amp stand, and gently removed the red cloth cover, they and I stood there for a couple of seconds, taking in the design. Then, almost simultaneously, the four of us sighed, "Wow."

The Pathos InPoL Legacy looks like something dreamt up by an Italian design house after one too many espressos from a La Marzocco KB90 (footnote 2). Both machines combine high-end industrial engineering with fearless visual swagger. The Pathos website alleges, "Through the years, the idea 'the uglier they look, the better they sound' has been common in the audio business." If that's a real trope, the Legacy torpedoes it. Its aesthetic clearly isn't an afterthought.

The movers left; my work began. Starting at the back, I locked onto the Legacy like a raccoon eyeing a picnic cooler. Dual gold-plated speaker terminals sit alongside three RCA inputs and three balanced XLR connections. The Legacy has no digital inputs nor a bay for an add-on digital board à la the FLS10. Four penny-sized, slotted covers hide the user-replaceable fuses. Finally, there's a master AC switch.

In typical Pathos fashion (footnote 3), the heatsinks on the sides of the amplifier are in the shape of the company logo. On the Legacy, the logo pattern is repeated six times on each flank. The joins between these 12 modules are clearly visible—slightly more so than the 18 flush-mounted screws that secure the two-part metal cover. This may bother sticklers who want a seamless, monolithic appearance and delight aficionados of an unabashedly industrial look.

On the front of the amplifier is a 16" × 5" convex panel made of padouk, a lovely reddish-brown tropical hardwood. Protruding horizontally from the top of this piece and rising a few millimeters above it is a silver cylinder. About 3" in diameter and 2" deep, it looks like either a circular display or an oversized volume knob. To my delight, it's both. I'll return to this.

On each side of this knob are three tubes: two Tung-Sol ECC803s—a premium, low-noise version of the more familiar 12AX7—plus one Sovtek 6H30, sometimes marketed with the "SuperTube" epithet (footnote 4) because of its excellent specifications. Pathos claims there is no need for biasing and that the tubes can last upwards of 10,000 hours.

I assumed that the 18 metal tube guards—each shaped like the blade of a small pocket knife—were positioned around the valves to reflect their glow. Same with the 8.5" × 4" mirror-polished metal panels placed next to the tubes at 45°: They seem designed to bounce and magnify, like angled mirrors in a candlelit room.

But I couldn't test this. I couldn't turn on the Legacy at all. The Legacy has an IEC mains socket, but it's of the C20 variety made for 20A loads, the kind with horizontal pins. The wheeled birchwood crate the amp arrived in contained no companion cable, with the C19 plug on one end, and I had none on hand. Also MIA was the amp's remote control.

The empathetic folks at Harmonia—the California-based Pathos distributor affiliated with Upscale Audio—pronounced these oversights "vexing and irksome" in a text to me (they're a literary bunch!). A-looking they went. Within a day, the missing items had surfaced; they'd been misplaced after an audio show where the Legacy had made an appearance.

Three days and one FedEx shipment later, music was finally in the cards. Sticking to my usual routine, I used the newly arrived cable to plug the amplifier straight into the wall, bypassing the AudioQuest PowerQuest PQ-707 conditioner that ably juices and protects the other electronics. Using AudioQuest Thunderbird cables, I connected the wonderful Estelon X Diamond Mk II speakers, which had temporarily stuck around in my gear closet after I'd rave-reviewed them for the January 2025 issue. For my digital source, I used an Aurender A20 streamer-DAC connected to the Pathos amplifier via Red River balanced interconnects. Later, I auditioned the Legacy with my reference speakers, a pair of Focal Scala Utopia Evos, and with the excellent Eversolo DMP-A10 streamer.

To get things going, it is necessary to move the power switch on the back panel to the up position. Actually turning the amp on, however, requires pressing an almost comically teensy button on the bottom left of the fascia; it's roughly the diameter of a medium-sized nailhead. You'll probably do this by feel a lot because that shallow control is more or less obscured by the padouk panel. An identical-looking button on the right lets you cycle through the six inputs, identified on the dual-character display as A1 through B3.

Primo piatto
The Legacy will be ready to play music about 30 seconds after power-up. Until then, a red, dotted P appears on the circular display. Does it stand for "Patience"? "Preparing"? "Please wait"? Or could it be "Pathos," "Protection," or "Purgatory"? The latter would be funny, a limbo where your music waits to be allowed into the world. Pathos says that "superior sonic performance" can be expected after 20 minutes. I found that to be true, although the sound continues to improve for at least another half-hour.

When the display is done P-ing (forgive me), it defaults to showing the two-character volume level, up to 99. You can't turn it off or dim it. In my mostly darkened room, I found this distracting, so I used LightDims, which are made of a mildly adhesive, half-transparent foil, like the material used to tint car windows. The rough circle I cut out with scissors tamed the Pathos's bright display perfectly. A six-sheet LightDims variety pack costs just $20 and will likely last you a lifetime (footnote 5).

About that volume knob: You have to use a little elbow grease—wrist grease I suppose—to turn it. Operating it with one or two fingers doesn't work, at least not easily: There's too much resistance. Increasing the volume from, say, 40 to 65 takes four 120°, full-handed turns, during which relays click rhythmically.

This minor workout may be for the best. The class-A Legacy is rated at 100Wpc into 8 ohms and 170Wpc into 4 ohms, reflecting the Legacy's MOSFET output devices. With the Estelons in the system, at the listening position, I measured 100dB peaks at 67 (two-thirds max volume); the Estelons have a sensitivity of 88dB/2.83V/1m. The Focals (92dB/2.83V/1m) responded even more vigorously: Things easily got loud enough for my most intense headbanging moments. I shudder to think of the clamor if you were to nonchalantly go past 75 on the dial.

I found it hard to ignore the partial dropouts—split-second reductions in gain—that accompanied every 0.5dB-step adjustment, as if the amp were stuttering. At the same time, a faint, percussive thwup emerges from the speakers with every stepped change. Harmonia's Jesse Luna relayed my experience to Pathos HQ in Italy and got the following response: "The volume control is a laddered resistor network that uses premium Vishay Dale metal-film resistors and individual relays, so the signal goes through one resistor per channel and comes out 100% pure. Because they're a mechanical device with a switching speed, there can be a very short delay between the devices responding." For maximum sonic purity, Pathos's engineers rejected the idea of inserting a mute circuit, transistors, or ICs into the signal path, at the expense of the tiny serial dropouts I mentioned. "These kinds of solutions would most definitely impact the overall sound quality in a negative way," team Pathos asserted. I can easily live with that decision.

What I couldn't brook was the Legacy's remote control. Even with a fresh battery, turning off the amplifier often required as many as a dozen power-button pushes. Curiously, that same button performed better—but still not reliably—when powering the Legacy on. The remote has gray icons printed on a mottled silver finish. Until you become familiar with the buttons and can operate them by feel, prepare to do a lot of squinting, if you are of a certain age. I eventually just kept the master volume at 60 and adjusted from there within the Roon app running on my MacBook Air.

Oh, and those tubes, surrounded by reflective metal surfaces I'd figured would help create a bit of mood lighting? Even in the dark, they emit only the faintest hints of light: pinpricks of orange, more ember than flame. It's subtle, not showy.

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Footnote 1: Look, ma, my first-ever American-football simile! This Dutch native may become a Real American® yet.

Footnote 2: See shorturl.at/HfQma.

Footnote 3: The only Pathos amps without those eye-catching fins are the T.T. (introduced in1994),the ClassicOne (1999), the Pathos Aurium headphone amp (ca 2013), and the more recent AmpliD—Pathos's first class-D amp, which of course runs cool and doesn't need such dissipation.

Footnote 4: So named, apparently, by Balanced Audio Technology's amplifier designer Viktor Khomenko; see shorturl.at/e3M6v.

Footnote 5: See lightdims.com/store.htm.