Designed and manufactured in the United States, Rogue Audio devices are still relatively unknown in France, despite their excellent musicality and value for money, as demonstrated by the brand’s entry-level integrated amplifier, the Sphinx, now in its third version. With two 12AU7 tubes in the preamp section and Hypex Class D amplification, the smallest Rogue Audio delivers a smooth, warm sound and comfortable power to both speakers and headphones. The icing on the cake is that it now has a phono input that can be adapted to MM and MC cartridges!
Beautifully hand-built in the United States under the direction of engineer Mark O’Brien, the Sphinx v3 introduces a range of three Rogue Audio integrated amplifiers. Less bulky, it uses the same components and hybrid design as the larger Pharaoh II (250 W into 8 ohms), while the Cronus stands out with a trio of 12AX7 double triodes and, above all, amplification on four KT120 pentodes. With its two dual 12AU7 triodes (also referenced as ECC82), the Sphinx v3 can be used as a pure preamplifier or as a headphone amplifier, while its primary function as an integrated amplifier benefits from the power output stage of a Hypex UCD180 card per channel, in class D topology.
The headphone amplifier has its own completely discrete Mosfet output stage, while volume control is handled by a 100 kilo-ohm ALPS 100KAX2 potentiometer, all placed on a printed circuit board made from a significant amount of pure copper. Located at the rear of the unit, the power supply is provided by a large 375 VA toroidal transformer custom-made for Rogue.
On its machined aluminium front panel, the Sphinx v3 features its raven logo in the top left corner, in white or black depending on the black or silver colour of the model chosen. Below this, a plastic power button is pressed to turn on the tubes once the switch on the rear of the unit has been activated. An orange LED indicates that the Sphinx v3 is in standby mode, while the other LED, which is initially red, indicates that it is warming up and turns blue when the amplifier is operational.
In the centre, a 6.35 mm jack socket allows you to connect headphones, while the right-hand side of the front panel features three plastic knobs, the first for selecting one of the four inputs, the second for balance and the last for volume control. A transparent plastic ‘skeleton’ remote control is supplied as standard, with three buttons for turning the volume up or down or muting it. A metal remote control from the American brand’s higher-end ranges is available as an option.
At the rear, everything is kept simple with four pairs of RCA terminals, three line inputs (the first of which is recommended for CD players) and a phono input, which since version 3 has been used to play both MM and MC cartridges, with a respective gain adjustment of 44 and 60 dB, in addition to RIAA playback with adjustable impedance, provided you unscrew the cover and play around with the pairs of switches according to the instructions. Set at 47 kilo-ohms as standard for moving magnet cartridges, the impedance can be adjusted in seven steps for moving coil cartridges, from 30 ohms to 1 kilo-ohm.
Two pairs of RCA terminals are added at the output, fixed for adding a power amplifier or bi-amplifier; variable for optimal adjustment to a subwoofer. And of course, located on each side and connected by cables to the internal power stages, two pairs of speaker terminals allow for the integration of a pair of fork or banana speakers, with a very high damping factor, announced by the manufacturer as over 1000, which is why feedback-related distortion is so low when listening.
The set-up
With a volume, dimensions and weight that are standard for a high-end amplifier, the Sphinx fits into any environment, provided that you make sure to connect it to RCA sources, as it only has unbalanced inputs. Already powerful, with a very high damping factor, it provides sufficient energy for our demanding Jern 15H speakers and is perfectly at home with more sensitive speakers such as our Closer Ogy or Solen HELios (reviewed in this issue).
A check on EgglestonWorks Emma Evo also confirmed its ability to power larger speakers, especially in the bass, but as the Sphinx v3’s speaker terminals are quite close together and small, we opted for fairly light cables from the Nordost Heimdall and Esprit Célesta ranges, rather than the Lumina from the French manufacturer that we still had on loan. First tested on its line inputs, the Sphinx v3 was then compared on its phono input to our Gold Note PH10. And as this version 3 can now be used with MC cartridges, we were able to listen to it not only on the Nagaoka MP-200 (MM), but also on the Hana ML and Skyanalog P1 MC cartridges.
The sound
As soon as it was switched on and the little red LED turned blue, the Sphinx v3 surprised us with its roundness and warmth. The preamp tubes are not yet fully warmed up, but the Class D power modules already surprise with their flexibility, far from the harsh or overly digital sound that can sometimes be heard with this type of amplification. Here, on the contrary, you would almost think you were dealing with a Class AB with the first watts in Class A, as the sound is musical and open, as well as truly warm.
When compared to a much more expensive amplifier, the smallest of the Rogue Audio integrated amplifiers never suffers in comparison, and while it doesn’t offer quite the same soundstage or precision, it never disappoints in terms of the quality of information reproduction, even when coming from a very precise source. Perfectly positioned in its price range, although more expensive than the previous version, the Sphinx V3 demonstrates real roundness and excellent timbre, with a preference for the midrange.
Even at low volumes, it has no problem providing sufficient energy to our Jern 15H speakers or relatively power-hungry floorstanding speakers, and at very low sound levels, its potentiometer manages to maintain maximum information and offers a very detailed listening experience that remains very flexible when you turn up the volume. However, especially with large symphonic and choral pieces, the soundstage loses some of its clarity, although solo voices are very well placed at the front. At very high volumes, electronic sounds become muddy with modern music, mainly in the upper end of the spectrum.
To test the self-powered headphone output, we not only had to plug in the headphones, but also mute the TV with the remote control so that the output stage to the speakers was switched off and only the preamplifier stage (i.e. volume control and source inputs) remained functional in the integrated amplifier, in addition to the headphone amplifier module. Then the small LED turned red again, and the music came out only from the headphones, slightly less warm and with less timbre than with the speakers, but still with enough power and flexibility to adapt to power-hungry headphones, including our Kennerton Thror orthoplanar headphones.
With the cover open so that the pair of switches can be changed to adjust the gain and impedance according to the cartridges (a step that only needs to be done once if you only have one cartridge, and not at all if you add a turntable with an MM cartridge that is already pre-set), the Sphinx from the brand with the perched raven can sing with the same fullness. With a finesse of reproduction almost equal to our mid-range separate phono preamps, it impresses just as much with an MM cartridge as with an MC cartridge, although the former suits it better, with a roundness that does not seek a raw sound, for example on rock, but a flexibility and listening comfort at all times.
Our conclusion
Our colleagues at Stereophile recommended we listen to this brand when we met them in Warsaw; we thank them for the idea! A little rough around the edges in its American style, without trying to flatter with plastic knobs or a very classic design, the Sphinx V3 is a true musical machine, superb in all its uses, whether amplifying speakers or headphones.
Equally impressive on its phono input, now also available (and configurable to seven impedances) for moving coil cartridges, Rogue Audio’s smallest integrated amplifier deserves to be compared to all the benchmarks in its price range, and even to models twice as expensive, to see if it isn’t already more than enough to provide listening pleasure at all times. And if it lacks power for very large speakers, you can always look to the larger Pharaoh II, or even the manufacturer’s separate amplifier and preamplifier components, which we hope to see more of at many retailers in France and Belgium in the years to come.
Author: Vincent Guillemin
Technical sheet: Rogue Audio Sphinx v3
- Origin: United States
- Price: €2,500
- Dimensions: 431.8 x 127 x 397 mm
- Weight: 11.3 kg
- Amplification type: Class D; tube preamplification
- Nominal power:
- 100 W at 8 ohms
- 200 W at 4 ohms
- Harmonic distortion (THD): <0.1%
- Frequency response: 5 Hz-20 kHz; +-1 dB
- Phono section: 44/60 dB MM/MC