Rogue Audio Ninety-Nine

Rogue Audio Ninety-Nine

Tube Line Stage Preamp

Frank Alles

26 September 2000


Frequency response: 1 Hz to 200 kHz ± 1 dB
Total Harmonic Distortion (THD): <0.1%
Rated output: 1.5 volts
Maximum output: 50 volts peak to peak
Gain: line stage 23 dB; mm phono 65 dB; mc phono 75 dB
Output impedance: 100 ohms
Dimensions: 17″W × 5″H × 14″D
Shipping weight: 35 lb.
Limited Warranty: 3 years parts/labor (6 months on tubes)
Price: $1,995. USD, $2,395 with phono option
Note: this preamplifier inverts polarity

Rogue Audio Inc.
2827 Avery Road
Slatington, PA 180080
Tel: 610/760-1621
Tech Support: 570/992-9901

“I found the Rogue 99 to be very quiet for a tube unit, exhibiting a low level of audible tube-hiss on my highly efficient InnerSound Eros speakers. For example, it is noticeably quieter than the Audible Illusions Modulus III, and the Bel Canto SEP-1…”

A couple of years ago, I reviewed Rogue Audio’s first commercial products, the model Eighty-Eight power amp, and the model Sixty-Six preamp, for the Audiophile Voice magazine. I found them to be very adroit all around performers and was particularly enamored of the amplifier. Now, Rogue Audio has introduced a tube line stage with an outboard power supply. Instead of using 6922 tubes, as is the case with many of today’s high-end preamps, they implemented a new circuit topology, employing four 6SN7 valves. Thus this, their flagship offering, has a new sound and some new features, while retaining the sedate retro styling of the Sixty-Six.

My review sample came equipped with Philips 6SN7 tubes, made in the USA, which is a $50 extra cost option when available. The standard tube compliment is of Chinese manufacture.

The Rogue Audio Ninety-Nine (99) includes a metal, brushed-aluminum-looking, remote volume control. The action of the motorized volume knob was just about perfect and it was nice to have the luxury of adjusting the volume from my listening seat. My one complaint regarding this control is that I could hear the motor noise through my speakers when the knob was being turned by the motor. The noise wasn’t loud, but it was a bit distracting and of course there was no noise when the control was turned by hand. Also, volume-control was the sole function of the remote. To access any other control (like the input selector) you have to use the manual controls on the preamp.

The front panel of the 99 contains 4 push buttons, for power, muting, switching to mono mode, and for activating the recording outputs on the rear panel. Facing the preamp, you’ll notice a large center-mounted volume knob. Lower, and to its left is a 5-position rotary switch that allows different gain settings, to optimize the gain level for use with different sources, amplifiers, and speakers. To its right, another 5-position switch selects one of 5 inputs, including phono (not connected on the line stage model, leaving 4 useable inputs in the absence of the optional phono board). The cost of the 4-tube phono board adds $400 to the $1,995 purchase price.

A total of 7 pairs of heavy-duty gold-plated RCA jacks are provided on the rear panel. Five pairs are inputs; there is one pair of main amplifier outputs; and one pair of switched recording outputs. There is also a standard ¼-inch stereo headphone jack–which would have been more convenient to access if it were located on the front panel. A female IEC connector is located on the remote power supply for use with detachable audiophile AC power cords.

Mark O’Brien of Rogue Audio seemed particularly proud of the heavy-duty power supply and intimated that it is capable of supplying copious clean voltage. That may be, but upon removing the cover to the outboard supply, and then to the main unit, I had to pause to wonder why Rogue chose this design. The outboard supply contains two ferric-core transformers laid side by side, while the larger high-voltage toroid is located on the chassis of the main unit, in close proximity to the circuit board. The dual-transformer outboard supply must be plugged into the main unit’s rear panel, via two multi-pin connectors with locking collars. I have 2 small caveats concerning the outboard supply.

First, the locking collars that I mentioned are plastic and they didn’t seem hold very securely when tightened. This means (at best) that the pins can cock at an angle, subjecting them to unwanted stress and (at worst) the connectors could weaken and eventually fail, or possibly be yanked out inadvertently at an inopportune moment. I realize that better connectors cost more money, but when you have a decent quality preamplifier, why attach the power supply with sub-par connectors?

Second, the outboard power supply on my review sample emitted a bit of mechanical hum when plugged-in to an AC outlet. This is not a fatal flaw, but I do consider it a minor annoyance, especially when many competing high-end preamps have no perceptible mechanical hum. Putting a weight on the supply helped a bit, but the hum was still audible a few feet from the unit.

While I’m in the nit-picking mode, I may as well say that I think that Rogue’s decision to omit a balance control on this model was ill considered. This is one feature that many folks (possibly even closet-purists) actually use, now and then. In the real world, there can be, and often are, inter-channel loudness imbalances.

Aural Impressions

“What I discovered, as I continued to listen, was that the lyric comprehension with the Rogue was well above average.”

My first impression of the Rogue Audio 99, was, in a word, “relaxed”. Nothing jumped out and bit me, and the presentation was smooth and well balanced. The bass was full and had substantial impact, but was somewhat less taut and articulate than that of some other preamps that I’ve used in my system. The treble was sweet and perhaps a touch soft, yet quite delicious—perhaps slightly laid-back.

The midrange seemed to have a bit more “presence” than I’m used to, and vocals, in particular, were mildly forward and presented a large image. On Fionna Apple’s “The Child is Gone,” from Tidal (Clean Slate/Work OK 67439) the cello and midrange of the piano were lush and warm. And listening to Counting Crows’ “Raining in Baltimore,” from August and Everything After (DGC DGCD 24528) the image of the piano was huge, resonant, dynamic and dimensional.

These early observations were made with the 99 sitting on a Townshend Audio Seismic Sink, which works well with most electronics, but was probably not the best choice for the Rogue. I found that inserting three # 4 Black Diamond Racing Cones between the 99 and the Seismic Sink did much to refine the sound of the piece. The high frequencies became more incisive, focused and extended, yet retained their smooth, non-irritating character. The bass articulation also improved, allowing me to hear more of the skin on drums and to better follow instruments like the electric bass. In fact, the precision and focus of the overall presentation improved considerably—so much so, that I felt the Rogue was performing at a level close to that of my custom AHT line stage.

What I discovered, as I continued to listen, was that the lyric comprehension with the Rogue was well above average. Listening to US 3’s “Different Rhythms,” from hand on the torch (Blue Note CDP 0777 7 80883 2 5), I was surprised to hear one phrase enunciated clearly, which is usually hard to decipher with other gear. The phrase in question, “This particular thing caught my ear,” on many systems, sounds more like, “This particular thing cut my hair.” With the 99 at the helm, the wording was clear.

Also, “Different Rhythms,” contains some tidy brushwork on the cymbals, and through the Rogue it emerged very distinctly—it was airy and soft as a cloud, yet well defined. Additionally, the bass and kick drum exhibited authoritative weight and impact that smacked of authenticity. Indeed, percussion was well served, as witnessed on Sousa’s “The High School Cadets,” from Fennel conducts Sousa(Mercury D 154637). Near the conclusion of the track the bass drum is simply bombastic and cymbal crashes on the left channel were quite potent and natural sounding.

The soundstage was very wide with very good retrieval of depth; and depth retrieval was an area that I found a bit lacking in my review of Rogue’s less-costly, model Sixty-Six preamp. But I was pleased to note that on Cake’s “Sheep Go To Heaven” from Prolonging the Magic(Capricorn 314 538 092-2) the backing chorus was clearly behind the lead singer at the left and right flanks of stage-rear. To my ears, the 99 outclasses the less-costly 66 in terms of its soundstaging and dynamic capabilities. The sonic character of the two siblings is certainly different, with the 99 being a more synergistic match for my taste and equipment. I have found that generally, compared to 6SN7-based preamps, 6922-based units seem slightly more extended in the uppermost octaves, but often have a mild prominence in the upper midrange/lower treble region, that highlights detail, but to my ears, sounds unnatural and distracting. Also, some 6SN7-based models (including the Rogue 99) pack more of a wallop in the low and mid bass regions, and seemingly, with a higher degree of control. Your mileage may vary…

I found the Rogue 99 to be very quiet for a tube unit, exhibiting a low level of audible tube-hiss on my highly efficient InnerSound Eros speakers. For example, it is noticeably quieter than the Audible Illusions Modulus III, and the Bel Canto SEP-1, although it’s not quite the equal of my super-quiet AHT line stage.

Also, the level of silence between musical notes, using the 99, was very respectable, though not quite as stark as what one hears from a good passive preamp or some ultra-regulated designs. That said, performance in this area can usually be improved by using an effective AC conditioner or an AC power regenerator like the PS Audio P300.


I must admit that I enjoyed my time with the Rogue Audio 99 preamp. Having remote volume control is a luxury for me. As noted previously, I was not particularly happy with some of the features and design choices that Rogue chose to employ. The important thing to consider is that Rogue is trying to market this product at a price that many audiophiles can afford. The basic design is sound, the overall build quality is decent, and the styling is elegant and simple.

In terms of pure sonic performance, the 99 provides a presentation that is well-balanced and dynamic, with decent articulation (depending on the base/feet used) at both high and low frequency extremes. With some material, it can sound a bit larger than life, but many people may like this effect. To my ears, the Rogue tended to soften the presentation just slightly, and it sounds a bit warm, or lush, from the bass through the lower midrange. Again, these are traits that will be synergistic in many systems (mine included) and are generally consistent with the sound of live music. Ultimately, I believe that the Rogue trades a bit of fine detailing and nuance for an enhanced sense of musicality; and many will view that swap as a positive.

If you’re the kind of person that obsesses about hearing all the minutia and subtleties of every recording, then you may need to continue your search. On the other hand, if your audio system tends toward the dry, lean, or edgy, the Rogue 99 may be your ticket to Paradise. For this latter group, the Rogue Audio 99 represents a musical oasis—where one can rehydrate one’s musical pores.

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