Rogue Audio Cronus Magnum III Integrated - Black

The Cronus Magnum III Puts Two Amplifiers in One Chassis

Rogue Audio builds the Cronus Magnum III by hand in Brodheadsville, Pennsylvania. It is an all-tube integrated amplifier, and it is the third generation of a line that built the company's reputation. Rogue designs and assembles every one in the USA.

A switch on the back panel changes how the output stage runs. In ultralinear it delivers 100 watts per channel. In triode it delivers 55. Transformer taps for 4 and 8 ohm speakers are both provided. The amplifier weighs 55 pounds and measures 18 inches wide, with a machined aluminum faceplate in black or silver.

Your Turntable Plugs Straight In, and So Do Your Headphones

Four RCA inputs cover a phono source and three line sources. Buffered variable outputs feed a subwoofer or a second amplifier for bi-amping. A quarter-inch headphone jack sits on the front, driven by a 2-watt amplifier. An aluminum remote handles volume and mute. Rogue covers the amplifier for three years, and the tubes for six months.

Why It Weighs 55 Pounds

Most of that weight is transformers and power supply. Rogue uses a large linear supply with high storage, and a heavy two-ounce copper circuit board. Slow-start sequencing brings the tubes up gently at switch-on, which is easier on them than an abrupt turn-on.

The tube complement is four KT88 output tubes, three 12AU7s and two 12AX7s. The center 12AU7 is the preamp tube. KT88s are current production and easy to source, so retubing years from now should not be a hunt. KT120s are available as an optional upgrade.

Bias the Tubes Yourself, With the Tool in the Box

A meter, potentiometers and switches on the front panel let you set the output tube bias. Rogue supplies the bias tool. The manual asks you to leave it alone unless a tube reads more than 4 to 5 mA off target, so this is an occasional check rather than a chore.

The Phono Stage Adapts to Your Cartridge

The phono section takes moving-magnet and moving-coil cartridges. Gain switches give 45dB or 60dB, each within 1dB from 20Hz to 20kHz. Five resistive load settings let you tune it further. It ships set to 45dB and 47k ohms, which suits most high-output cartridges.

Changing gain or loading means removing the top cover, so set it once for your cartridge. Bandwidth measures 5Hz to 30kHz within 1dB. Distortion stays under 0.1% typically and under 1% at rated power. Input sensitivity is 1.0V RMS.

The headphone circuit is new to this generation. Rogue describes it as a simplified single-ended version of its RH-5 headphone amplifier, built around MOSFET buffers, with a 32-ohm output impedance.

What Reviewers Are Saying

Wayne Garcia, writing in The Absolute Sound on January 24, 2023, called it "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."

Ron Nagle, reviewing for Enjoy the Music.com on May 7, 2019, wrote: "Rogue Audio has my admiration for the overall build quality and sonic performance of their Cronus Magnum III musical instrument."

Who Is This Integrated Amplifier Best For?

• You want tube sound without a rack of separates — preamp, power amp, phono stage and headphone amp are all in one chassis.
• You play vinyl and your cartridge might change — the phono stage handles moving-magnet and moving-coil, with switchable gain and five load settings.
• You want to hear the difference between operating modes — a rear switch moves between 100 watts ultralinear and 55 watts triode.
• You like gear you can maintain — front-panel bias adjustment, a supplied bias tool, and KT88 tubes that are still in production.
• If you want the DAC and streaming built in, the Cronus Magnum III is all-analog — every input on the back is an RCA jack. Add one of our DACs and it plays anything.

How Does It Connect to Your System?

Speakers go to the gold-plated binding posts, which take spade, lug or bare wire. Pick the 4 or 8 ohm tap for your speakers; the amplifier ships set to 8 ohms, and changing it means opening the top cover. Your turntable goes to the phono input, and up to three more sources fill the line inputs.

Headphones plug into the front panel. If you add a subwoofer or a second amplifier later, the buffered variable outputs are already there. The power cord is a detachable IEC, so you can change it.

Then it is one knob, one switch, and a lot of glass.

Pairs Well With

Building around the Cronus Magnum III? Here are some good companions:

• Turntable: Put that MM/MC phono stage to work — see our Turntables.
• Speakers: 100 watts of tube power drives a serious pair — see our Floorstanding Speakers.
• Speaker cable: Match the tap you choose — see our Speaker Cables.
• Audio rack: Fifty-five pounds of tube amp wants a solid shelf — see our Audio Racks.

Frequently Asked Questions

How much power does the Cronus Magnum III deliver?

100 watts per channel in ultralinear mode, and 55 watts RMS per channel in triode. Transformer taps are provided for both 4 and 8 ohm speakers.

What is the difference between triode and ultralinear?

They are two ways of running the same output tubes, selected by a switch on the back panel. Ultralinear gives you the full 100 watts per channel; triode gives you 55. Rogue's own guidance is to try both with your speakers and use the one you prefer.

Does it have a phono stage for my turntable?

Yes, and it covers both cartridge types. Switchable gain gives 45dB for moving-magnet and high-output moving-coil cartridges, or 60dB for low-output moving-coil, with five resistive load settings.

Do I have to bias the tubes myself?

Bias is user-adjustable from the front panel using the meter and the bias tool Rogue supplies. The manual says to leave it unless a tube drifts more than 4 to 5 mA from target, so it is a periodic check rather than routine maintenance.

What comes in the box?

The tubes, spare fuses, the bias tool, an aluminum remote for volume and mute, and a detachable IEC power cord. The full tube cage is optional and sold separately — we stock the Rogue Audio tube cover.

What warranty does it carry?

Three years on parts and workmanship from the date of retail purchase, and six months on the vacuum tubes. Rogue's warranty is valid in the United States and applies to the original purchaser buying from an authorized dealer.

See It in Action

New Record Day spends a full review with the Cronus Magnum III and asks where it lands among tube integrateds:

Sheila Berdan unboxes one and walks through the chassis, controls and rear panel:

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