The Rogue Audio logo includes a silhouette of a bird that I am told is a raven, the largest member of the crow family. This was chosen because the raven is an intelligent bird that doesn’t travel in a flock. It turns out that Rogue MD Mark O’Brien is what the Americans call a ‘birder’, or ‘twitcher’ as we know them, so I guess some kind of winged beast is appropriate. Regardless of logo, Rogue makes some remarkably affordable electronics given that it builds them in Pennsylvania. Even by the time you add import duties and our bludgeoning levels of sales tax (VAT), this integrated with phono stage comes in at under £2,300, which must make it the least expensive example of the made-in-USA breed on the market. In fact, Rogue does make a less expensive model, in the Sphinx: a hybrid with a Class D output stage.
This Cronus Magnum is the latest incarnation of a model that has been in the Rogue range since 2005. It started out as simply the Cronus, an EL34 push-pull, and evolved into the Magnum Cronus four years later, which saw a switch to KT90 output tubes. The KT120 pentodes you see before you replaced the KT90s in 2012, in order to provide more power and thus greater ease of speaker matching.
It’s long been the bane of tube amplification that limited power means limited speaker choice, but the KT120 – one of the most recent additions to the ranks of output pentodes – was created to deliver the sort of power that most glass lovers could hitherto only dream about. It was introduced three years ago, and in that time has almost usurped the 6550 that was the staple of many power amps. It’s appeal is power; Rogue specifies that the single pair on each channel of the Cronus Magnum is good for 100 watts, a bruising output for any tube amp, let alone one at this price.
Rogue has decided to make this amp a manual bias type and provides not only an easy access series of trim pots, but also a suitably skinny driver with which to adjust them. Following the instructions provided, it was refreshingly easy to check each tube and tweak where required, and in this case only one had drifted. The driver tubes are standard 12AU7 and 12AX7 types, which means they are easy to replace, or roll should the urge take you. The glassware is given a soft start at turn on in order to preserve tube life, and Rogue estimates that the KT120s should be good for two to three thousand hours.