Rogue Audio Magnum Ninety-Nine preamplifier

Rogue Audio's Magnum Ninety-Nine tubed preamplifier is derived from the original Rogue Sixty-Six that I reviewed in October 2000. The Sixty-Six was designed to offer consumers a taste of high-end performance in a vacuum-tube line stage. By constrast, the Magnum Ninety-Nine's pedigree is pure audiophile, with a more sophisticated mu-follower circuit topology aimed at the purest expression of performance.

"We eliminated the balance circuit for that reason," O'Brien explained. "It loaded down the input a little bit, but we still included mute and mono switches, and a headphone input on the back of the chassis, as well as an adjustable gain control.

"[The Ninety-Nine] was designed to function as standalone performer," said chief designer Mark O'Brien, "with a high enough input impedance and low enough output impedance that it should work well with almost any amplifier. We didn't want to box people into thinking they had to have a pair of our monoblocks in order to get the most out of the Ninety-Nine."

The Magnum version of the Ninety-Nine uses: Raimond Mundorf film and foil capacitors and Dale-Vishay resistors in the signal path; a significantly tweaked, more massive external power supply; gold tube sockets; premium silver wiring; and primo New Old Stock tubes, in this case vintage chrome-dome Sylvanias. But while the Sixty-Six's tube complement comprises two 12AU7s and four 6DJ8/6922s, the Ninety-Nine uses four twin-triode, octal 6SN7s, which are larger than the nine-pin triodes we've grown used to seeing in preamps.

"The 6SN7 is just a wonderful-sounding tube," O'Brien told me, "parametrically similar to a 12AU7 but much more linear in its gain characteristics—which make it ideal for use in a preamp. It's just rich with information and elicits a lot more musical details than other tubes I've heard, without sounding either overly analytical or euphonic."

In addition, Rogue has set aside a number of open bays in the Ninety-Nine that allow for future mods and upgrades, such as a plug-in (ie, no soldering) MM/MC tube phono board. And for nominal fees, Rogue is more than willing to accommodate requests for custom features, such as the second set of tape outputs in my review sample.

"When configured in the active mode [via an internal mini-switch], the tape outputs are able to drive a subwoofer. Then the Record button acts as an On/Off switch—whereas, when using it to drive tape, you'd switch to the passive mode."

My system was essentially the same as used for my review of Rogue's Magnum M-120 monoblock in the December 2002 issue—save for the absence of said power amps during my conclusive listening trials. (They'd been shipped off to John Atkinson's for a final round of tests, measurements, and spa cuisine.) I wrapped up my evaluations of the Magnum Ninety-Nine by pitting it against the Musical Fidelity Nu-Vista and VTL TL-5.5 preamps on their home turf: with their very own power amps, the hybrid MF Nu-Vista 300 and the tubed VTL MB-450 monoblocks.

The original review sample of the Magnum Ninety-Nine included the optional phono stage, but the Grado Statement Master cartridge's output of only 0.05mV made it a less than ideal match. "The phono stage performs very well with most moving-magnet and high-output moving-coil designs," O'Brien explained. "But the reduced dynamics and higher noise you experienced are typical of the response you'd anticipate in cartridges with an output below 0.075mV." He suggested I try Rogue's standalone solid-state unit, the Stealth ($795), which I used with a second line-stage-only sample of the Ninety-Nine.

Rogue Audio
2827 Avery Road
Slatington, PA 18080
(570) 992-9901