Rogue Audio RP-5 Preamplifier

Equipped with remote control, phonostage, four unbalanced RCA inputs, microprocessor control, and even a trendy front-panel headphone output, the Rogue Audio RP-5 is a handsome, full-featured preamplifier that’s thoroughly modern in every sense of the word. You won’t find any grass growing beneath its anti-resonant footers. But it’s also brimming with classic vacuum-tube virtues that brought back personal memories of an earlier era in the high end. Specifically, from the 1970s, when owning a high-power solid-state amp was the strongest incentive to purchase a tube preamp. Anyone who came of age during that period knows what I’m talking about. Solid-state output devices and topology were still in their relative infancy, and while these beasts were powerful, stable, and even sonically praiseworthy in some areas, they had already developed a bad-boy reputation for a dry top-end, as well as an off-putting graininess of texture in the treble region. On the other hand, tube electronics, the established old guard, while relatively low-powered in comparison (and often encumbered with colorations of their own), still possessed a fluidity and warmth that solid-state couldn’t approach. Audiophiles seeking to take advantage of solid-state power without giving up the sonic qualities of tubes often resorted to a hybrid solution—a tube preamp placed in front of a transistor amp could ameliorate the more offensive behavior, smooth over the grain, and add the bloom and warmth that solid-state so sorely lacked. Clearly as the years passed the attributes of tubes and solid-state began to converge until the sonic differences today are of a lower magnitude. But for many of us a tube/solid-state electronics chain remains a very compelling solution.

No doubt about it, the RP-5 is one good-looking hunk of electronics. A central oval display is centered on its brushed-aluminum front panel with a large aluminum volume knob on the right side, microprocessor-controlled input buttons along the bottom, and a balance knob on the left. The bright VFD display provides volume, balance, and source info in large, readable characters. The volume control is a stepped-attenuator with 60 steps in 1dB increments. There are no op-amps in its signal path. Adjusting balance over 66 steps is as easy as giving the knob a spin, but Rogue has also added a return button beneath the balance knob that when pushed will automatically rebalance the two channels. Very clever, and an example of what good software engineering can accomplish.

The headphone amplifier is fed from the outputs of the tube gain stage. The RP-5’s headphone amplifier is a tube/solid-state hybrid that offers sufficient power for more-difficult-to-drive higher-impedance headphones. Other features include home-theater inputs, a processor loop, and a mono button. The ten-button remote allows access to volume, balance, selector, mute, mono, and on/off from your listening position. The RP-5 also features a “slow-start” turn-on sequence and automatic muting when powering on or off. Every RP-5 is fully tested, burned-in, and auditioned prior to shipment.

Internally the tube complement is four 12AU7/ECC82. Rogue employs a mu-follower—a high-gain, low-output-impedance inverting stage known for low noise and very low distortion. Classic old-school tube stuff. But on the modern end it’s also the first preamplifier to be based on Rogue’s RP-X platform—a formula of hardware and software that will be the basis for the brand’s future preamps. The software has been developed in-house and will allow the company to bring more functionality to its designs. “Top” Rogue and President Mark O’Brien stated that “the goal was to create vacuum tube preamps that not only sound extraordinarily good but included the modern feature-set that our customers are looking for. The tube circuitry is now computer-optimized for extreme accuracy, ultra-quiet operation, and long-term reliability. The RP-5 also has features such as a vacuum-fluorescent display and the ten-button remote, which would not be possible without the new hardware and software package.”

Turning to sonic performance, the RP-5 did not immediately strike me as a tube preamp in any Old World sense. To begin with it was very quiet—solid-state quiet. No valve whoosh, chug, or hiss. Even as it idled and I applied increasing amounts of gain, the sonic result was the same silent, inky-black background. Tonally, the RP-5 was predominantly neutral with just a very subtle hint of a rose-blush complexion to warm the mids. The treble was nicely extended, quick, detailed, and replete with harmonic information. Bass performance was authoritative, very nicely controlled and musical, yet also adding small amounts of bloom to bass violin, timpani, and cello. Transient behavior was quick off the mark but naturally so—firmly struck notes from a piano, a flatpick, a rimshot, a trumpet presented a complete picture of the initial transient, the sustain of the note, and its trailing decay.

The RP-5 especially brings its magic to bear in the areas of color saturation and tonal liquidity. A prime example would be how vividly the RP-5 reproduced the contrasts in the intricate vocal harmonies and acoustic arrangements of neo-bluegrass band Nickel Creek [This Side]. The RP-5 had the ability to balance the competing images in much the way we experience them in life—individual and apart in space, yet at the same time locked together in performance. In the instance of Nickel Creek, mandolin, acoustic flattop, and vocals resided unwaveringly in their own pockets of ambient air—utterly stable, with no smearing. And they did so effortlessly, without sounding clinical or over-articulated. The RP-5 simply presented a natural acoustic clarity that rang truthful. The preamp had an inner resolving power that established a sense of dimension and space so specific to each image that I was almost able to isolate each player visually, as if I were attending a live concert.

Since Rogue outfitted the RP-5 with a phonostage as standard equipment, I wasn’t going to let the opportunity pass me by to put my Sota Cosmos/SME V rig through its paces. Optimizing the phonostage for the Sumiko Palo Santos Celebration was an easy task. It required removing ten cover screws, and lifting away the aluminum top plate. Once inside there was easy access to a pair of red slide switches for capacitance, plus DIP switches for eight settings of resistive loading and four gain settings between 40 and 60dB. Total work time was about five minutes, and I was being very careful. I can understand those who consider the effort an imposition, but consider the fact that, one, it’s not something you do every day, and two, in contrast with the convenience of front-panel phono adjustments, placing the phono switching so close to the phono circuitry reduces the distance that the signal has to travel and thus potentially reduces noise. As an aside, opening the cover made it easy to appreciate how neatly laid out the RP-5 interior was, including the expensive Mundorf caps, and the relative isolation of the sensitive phonostage nestled in a corner well away from the rest of the circuitry.

Turning to the phonostage performance, overall imaging was stable and transients retained their spontaneity. There was solid underlying continuousness across the soundstage, as well. However, I heard a lighter energy and cooler cast in familiar recordings. The sound wasn’t quite as richly varnished compared with other sources I’d input through the RP-5. One instance would be the new Impex LP remastering of Jennifer Warnes’ Famous Blue Raincoat. During “Song For Bernadette,” Warnes’ vocals seemed a little less rich and colorful, and the airy buoyancy of her head-tone was a dash drier. I have to confess the phonostage was a little bit disappointing given the overwhelmingly positive nature of the experience up until that point. However, to be fair, I was running the phono at maximum gain for the benefit of the Palo Santos Celebration moving coil (0.5mV), and though it was reasonably quiet for this class the RP-5 phono section couldn’t match the seriously quiet Parasound JC3+, proving once again that I’m spoiled, and that it’s hard to beat a premium outboard phonostage for isolation. For a built-in phono with this level of optimization, it still represents good value.

Rogue Audio is an instance of an American high-end company whose name may not instantly ring bells of recognition, at least compared with the zoom factor of more costly headliners like ARC, VAC, CJ, or Pass Labs. Nonetheless, a reasonably priced, high-performance preamp like the RP-5 is a prime example of what the high end is all about—music reproduced accurately and beautifully. With a nod to the past and footers firmly planted in the now, the RP-5 is a component that should tempt a lot of people to go Rogue.

SPECS & PRICING

Inputs: Four RCA, one phono
Outputs: Two variable RCA, one fixed
Dimensions: 18.5″ x 4.5 ” x 14.5″
Weight: 30 lbs.
Price: $3495

ROGUE AUDIO, INC.

PO Box 1076

Brodheadsville, PA 18322

(570) 992-9901
rogueaudio.com