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.
Build quality is solid but not fancy. Knock the top plate with your knuckle and it clonks in a rather uninspiring way, but it’s purpose is to protect you from it and vice versa, nothing more. Lift the amp up, however, and you may be surprised at how heavy it is. The ironwork must be extremely dense, which means that the whole thing is pretty much theft proof. I like the aluminium face plate and the low profile nature of the chassis, but it’s obviously not built to look pretty. You can get an optional cover that makes it look marginally less industrial, but if you want style the Rogue may not be the amp for you. The remote handset on the other hand is rather nice. It’s carved from solid aluminium and equipped with two volume buttons; it’s quite at odds with the aesthetics of the amp.
Connection wise, the Cronus Magnum has three line inputs plus phono for moving magnet cartridges, outputs for a sub or bi-amping, and the speaker outputs connect to four and eight Ohms taps. But whichever tap I chose I couldn’t get this amp to produce solid bass with the first speaker I connected it to, using Townshend Isolda DCT cable. That speaker was the ATC SCM11 – not a brand that’s renowned for its tube friendliness, I’ll grant you, but Rogue does say 100 watts per channel in the spec. The mid and top was a lot more successful however; voices were beautiful and the guitar work righteous on Steely Dan’s ‘Bad Sneakers’ [Katy Lied, MCA]. Winding up the volume on this combo, it became apparent that the IR remote works at some pretty extreme angles, so the handset is not merely a looker.
Moving onto a rather less demanding loudspeaker in the form of PMC’s fact.8 floorstanders, the unvarnished demos on the Denmark Street Sessions partner disc to Fink’s Hard Believer [Ninja Tune] delivered a directness that gave them greater emotional power than the finished versions. The bass lines on ‘Pen on Paper’ were particularly effective, revealing that the Rogue can do bottom end when the speaker is not putting up a fight. More important is the way that the amp lets you hear the intent and feeling in the music, the lyrics are clearer so the meaning of the song is easier to appreciate. It makes for very engaging listening. This much was apparent with Gregory Porter, too; he has a honeyed voice but there’s a sting in its tail, yet it’s not too smooth because there is real feeling behind songs like ‘No Love Dying’ [Liquid Spirit, Blue Note] and clear reverb on the voice and instruments. Reverb is always more obvious with tube amps, either because they have such good midrange resolution or because of the harmonic distortion that these devices introduce. But in this case, it’s subtle enough not to matter; if it’s a distortion it’s a euphonic one.
By transistor standards, the bass is still slightly soft edged, but it has pace, shape, and adequate weight. People like tube amps partly because they don’t like the grain that many transistors add to the mix, but solid state devices do give lower frequencies better definition, so it’s a case of choosing your poison. High frequencies here are not as extended as a good solid-state design but do sound smoother, which can be a benefit with many loudspeakers. Cymbals here are a little thin, but brass is excellent. You get the tonal richness without the glare that is so often evident. The Cronus Magnum also copes with high density material with ease, making the music easy to follow because the rhythms and melodies are never buried in the arrangement.
The softer high frequencies don’t give the full height that some alternatives can, but the soft-edged presentation can work wonders for strong piano recordings such as Brendel’s The Complete Beethoven Sonatas [Philips]. Possibly because this is a digital recording it can sound hard, but here you get the remarkable fluidity of the playing, and your attention is drawn to the tremendous dynamics that Brendel delivers; it’s a totally engrossing performance. With more contemporary material such as Lorde’s ‘Royals’ [Pure Heroine, Universal], which is very much an in-the-box production, the whole thing sounds strained and small scale, as the compression used is rather too obvious. Exposing the shortcomings of commercial studio techniques is often, but not always, the price you pay for great results with good recordings.
An example of the latter would be Patricia Barber’s ‘A Touch of Trash’ [Modern Cool, Premonition]. On that track the bass playing could be tauter as it’s both slower and thicker than I am used to, which is hard to ignore. The drama of the piece is well served, however, and the trumpet remains rounded and distinct without getting too bright up at volume.
I decided to give the phono stage a go, which meant digging out a vintage Audio Innovations step-up transformer and finding somewhere to site it that didn’t induce hum. Not an easy exercise, but a fruitful one as the results achieved with a Rega RP8 and Apheta MC cartridge were very appealing. Vinyl is generally more open than digital and that proved to be the case here; the Rogue phono stage also had more life and vibrancy if perhaps less precision than the line inputs. However, I was impressed with how quiet the phono stage is and how powerful and engaging it makes vinyl sound. Moving over to a Dynavector P75 Mk3 phono stage produced an increase in detail if not in pace, which is clearly good with the onboard stage. The external stage does, however, deliver more of the atmosphere in recordings by virtue of greater transparency. That said, if you are into vinyl for its sheer musicality (and this is no small reason for its revival), then the Cronus Magnum’s phono stage is easily up to the job (and all the more so if you have a moving magnet cartridge).
The Rogue Cronus Magnum is a great amp for the money. It eschews fancy casework in favour of solid engineering and great sonic results. You pay a small levy for having it built where it’s built but, as British motorcycle fans realise, in the long term these things do matter.
Type: Tube, two-channel integrated amplifier with built-in phono stage.
Tube complement: (2) 12AX7, (3) 12AU7, (4) KT120 output tubes
Analogue inputs: One MM phono input (via RCA jacks) , three single-ended line-level inputs (via RCA jacks).
Input impedance: High-level: not specified; Phono: 47kOhms
Power Output: 100Wpc @ 8 Ohms
Bandwidth: 20Hz – 30kHz
Distortion: Not specified.
Signal to Noise Ratio: Not specified
Dimensions (HxWxD): 140 x 457 x 432mm
Accessories included: 1.5m KEMP Lo Power Cord
Manufacturer: Rogue Audio
UK Distributor: Divine Audio
Tel: +44(0)1536 762211
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