Rogue Audio Cronus Magnum III Integrated Amplifier

Spoiler alert—I love this amp!

By starting with such a bold statement, I don’t mean to suggest that the latest iteration of Rogue Audio’s Cronus Magnum is without flaws. (What is?) I’ll get to that later, but for now let me begin with this: Here we have a terrific-sounding, all-tube integrated amp that is so musically engaging, such a joy to use, and such a superb value that it’s completely won me over.

Actually, it’s won me over for a second time, as a decade ago I was likewise highly enthusiastic about Rogue’s original Cronus Magnum. But as good as that version was the latest iteration punches several levels above, thanks to a slew of tasty upgrades.

Designed by Rogue Audio’s owner Mark O’Brien, the all-tube Cronus Magnum III ($3495) features an upgraded triode preamp circuit coupled with Rogue’s Atlas Magnum power amp (which goes for $2995 as a stand-alone unit). The III version also incorporates improved component parts throughout, a beefier power supply, as well as refashioned low-voltage supplies for the MOSFET, buffered, discrete headphone circuit and the phono section. I’m also pleased to report that the latter now handles both mm and mc cartridges, with five user-adjustable load settings, as well as 45dB and 60dB gain options.

(One thing to note: If you live near a radio transmission tower—as I do, about a five-mile straight shot across the hills from my house in San Francisco—the Magnum III’s phonostage is sensitive to RF. So, take extra care with placement as well as cable dressing to minimize this extraneous noise. It’s not particularly noticeable with most music but can be during quiet or between-track passages.) 

The design’s tube complement (two 12AX7, three 12AU7, and four KT120 output tubes) now allows users to switch “on the fly” between triode or “ultralinear” (pentode) output modes, and power output has increased from 90 to 100Wpc (half of that when operating in the triode mode). The gold-plated binding posts can be rewired to optimize speaker matching for 4- or 8-ohms loads but note that, as with the original design, users will need to remove the amp’s top plate to rejigger the wiring at the posts (as well as to change the phono settings). The process takes a few minutes but is otherwise pretty straightforward.

Also, as with the original edition, a handy, removable, small rectangular top plate allows easy access to the bias adjustments for the output tubes—the supplied plastic screwdriver even has a convenient resting nook tucked behind the tube array. Biasing is a snap to accomplish and something owners will want to check every few months, as well as down the road when a new tube set is installed.

Finally, a machined aluminum remote allows for volume control as well as muting, but you’ll need to get your bum off the couch to switch inputs.

I should also note that everything about the design, build, and fit and finish is first-rate, reflecting the company’s dedication to quality.

Sonically, the Cronus Magnum III is really quite remarkable, especially when compared to the far pricier gear I’m used to in my reference system. No, it doesn’t provide the same degrees of resolution, staging, detail, and dynamics as my references. But then that’s like expecting a village Burgundy to compete with a grand cru. That’s hardly the point of the design. Because the thing is: This amp is musical; it rocks; it’s fun; and lo and behold, it isn’t tweaky. It’s warm sounding but not fat; it’s airy; its resolution is plenty satisfying. It is simply very, very good. The Magnum III’s is not a “wow” kind of sound but rather a let’s pull you into the music kind of sound.

For example, on Analogue Productions’ stunning-sounding UHQR of Are Your Experienced? Mitch Mitchell’s drums on “Waterfall” are tuneful and natural, rollicking along with Hendrix’s dreamy guitar work; Noel Redding’s bass at once anchors things, while floating with the musical tide.

On “Fire,” you really hear and feel the distorted crunch of Hendrix’s Strat/Marshall combo, as well as key in on the album’s mic placement and mixing, which you’ll notice changes from track to track, bringing Hendrix’s potent debut to life. 

One caveat for owners of power-hungry speakers like my Maggie 1.7i’s shouldn’t surprise: A bit more additional punch and power would be a welcome thing. But then again, most speakers aren’t as demanding as Magnepans are. And when it does top-out, the Magnum III doesn’t go into distortion mode but comfortably cruises along at its maximum volume setting.

Another caveat. As with the original Magnum, the III does overlay a fine granular texture on the sound. It’s noticeable but not a major distraction. In some ways it’s actually a kind of cool additive. On “Two of Us,” from the Beatles’ 50th anniversary edition of Let it Be, one really senses the sound of the vintage analog gear; Lennon and Harrison’s Epiphone and Gibson guitars plugged into Fender amps, the thick strings and warm tonality of Paul’s signature Hofner bass, and the skin-and-wood tonality of Ringo’s Ludwig kit.

Moving on to Bill Evans’ Complete Sunday at the Village Vanguard shows the amp’s way with a great-sounding live acoustic set. Right away you’ll notice the acoustic ambience and three-dimensionality of this famed venue’s space, the natural feeling of air surrounding the instruments, the tonal and textural resolution of the piano, bass, and drums.

Finally, turning to my well-loved DG LP of Evgeny Kissin’s live recital of Beethoven’s Piano Sonata No 32; while the Magnum III may be missing the nth degree of focus, tonal purity, dynamic nuance, and lower octave drive of the far pricier Sutherland and VTL gear of my reference system, the hypnotic second movement, with its ragtime-like bridge, really shines, drawing one into the emotional and intellectual power of this piece, with its lovely harmonic richness leading to the final and breathtaking denouement. 

Circling back to my initial points about imperfections, and that all designs possess them—why else keep pushing the envelope?—it’s interesting to think about how, throughout audio history, certain memorable designs have identifiable shortcomings that don’t greatly detract from their overall excellence. I’ll cite the original Quad electrostatic speaker, the Rogers L3/5A mini-monitor, and the Audio Research SP6 preamp as examples of designs that so wonderfully capture the gestalt of the music that we’re able to live with and listen past their imperfections, because they are so very good at drawing us into and conveying the music.

Each of those designs is, of course, considered a classic. I can’t say if Rogue’s Cronus Magnum III will stand that test of time. But I will say that, in its own way, it is just as deserving.

Specs & Pricing

Power output: 100Wpc
Tube complement: 3x 12AU7, 2x 12AX7, 4x KT120
Inputs: Phono, Line 1, 2, 3
Dimensions: 17.5″ x 6.75″ x 18″
Weight: 55 lbs.
Price: $3495

Rogue Audio, Inc.
545 Jenna Drive
Brodheadsville, PA 18322
(570) 992-9901
rogueaudio.com