In an email conversation I asked Rogue Audio’s founder Mark O’Brien about the primary aim in designing the RP-7. He replied that “the overarching sonic goals were high levels of transparency and dynamics along with a super-low noise floor. If the circuit layout is executed properly you will also get a great soundstage. I tend to design our flagship models based on what I want in my own system at home, so besides great sound I also wanted a full-featured preamplifier. I appreciate the flexibility of having lots of inputs, a processor loop, and the ability to seamlessly integrate the preamp into a home-theater system.” He went on to add that “you are ultimately listening to the power supply so I focus a great deal of attention and design budget in this area. In the case of the RP-7 there are 17 different power supplies, almost all of which are fully regulated. The high voltage tube supplies are probably much larger than they need to be, but the end result is a very low noise floor and great dynamics. Each of the tube filaments is also individually regulated for low noise. The RP-7 design is far too complex to be implemented with point-to-point wiring so we use very high quality, military-spec circuitboards with heavy copper. Exotic parts include oil-filled Mundorf coupling capacitors, Vishay resistors, and Vishay HEXFRED diodes, among others.”
Sonically the RP-7 advances upon the musicality of the RP-5. Like a family member that attended finishing school Rogue has taken the musical voice of the RP-5 and further burnished its performance in areas that were already very, very good. What remains is the “rose-blush complexion” that warms the mids—the harmonic cushion and velvety textures are all present and accounted for. In fairness, the RP-5 didn’t strike me as possessing an old-world, tubey signature, but it nevertheless conveyed vestiges of that classic warmth and romance—some modest colorizing that I regard as hugely musical. The RP-7 steers a little further away from that inviting glow, but achieves a purity factor in its tonal presentation that is more discernably neutral, with greater dynamic clout, a sweeter top end, a weightier tonal spine, and increased fluidity and polish. Its dynamic envelope was simply wider across the micro and macro expanses, its transients quicker off the mark.
Perhaps most importantly, there is also a newfound solidity and control in the bass and lower midrange that more securely anchors the music—from a rock band to an orchestra. This was a trait I immediately clocked when I cued up the hit “Just What I Needed” from the Nautilus pressing of The Cars’ eponymous debut LP [Elektra]. The track had the tight, crisp drum and electric bass groove that Top 10 pop records are built on. In comparison, the RP-5 had a more relaxed attack. The RP-7 removed a little bit of that softness, giving the music a stiffer sounding board for transients to ricochet off. I could hear the improved immediacy every time I could discern the location of a tambourine or mandolin, an acoustic guitar or a snare rattle or rim shot within the soundstage. Importantly, the bloom factor remains strong when it came to bass violin, timpani, and cello. Vocalists, such as a cappella songstress Laurel Masse from the album Feather & Bone [Premonition], were better focused and more stably imaged, which added to a stronger three-dimensional presentation while also reproducing acoustic venues with greater depth.
The RP-7 zeros in on tonal clarity and color saturation with the best of them in this bracket. Not only did the Rogue better reproduce music’s micro-dynamic gradations, but it also achieved a more finely tuned sense of texture. As I listened to Beethoven’s Ninth with Solti conducting the Chicago Symphony [Decca] the personalities of each orchestral section—woodwinds to brass to strings—were depicted with a wider range of expressiveness and contrast. The RP-7 was so respectful of the tonal and timbral qualities that make up each of these groups it was as if the preamp had undergone advanced sensitivity training.
Much more than merely a “signature” edition, the Rogue Audio RP-7 represents a significant upgrade over the excellent RP-5, ascending to an entirely different class. In virtually every observable parameter it surpasses its lower-priced sibling, while aggressively holding the line against the worthy competition it will encounter in a more demanding and expensive market segment. Surpassing expectations? Just another day in the life of a Rogue.
Specs & Pricing
Type: Vacuum tube preamp
Tubes: Four 12AU7/ECC82
Inputs: Three RCA, two XLR, unity gain, processor loop
Outputs: Two RCA, two XLR, one fixed
Dimensions: 18.5" x 4.5" x 17"
Weight: 30 lbs.
ROGUE AUDIO, INC.
P.O. Box 1076
Brodheadsville, PA 18322