Rogue Audio RP-5 Preamplifier

An Old Soul

Equipment report
Categories:
Tubed preamplifiers
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Products:
Rogue Audio RP-5
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.”