Rogue Audio RP-7 line preamplifier

You know I'm a lucky guy. I maintain two separate audio reviewing systems.

The core component of my beloved, daily-driver desktop system is a Mytek Brooklyn DAC-preamp-headphone amp. Through this system I play high-resolution files and Internet sources (Tidal, Qobuz, Netflix, and YouTube). One of the Brooklyn's two line-level inputs delivers NPR news and baseball from my Kenwood KT-990D FM/AM tuner. I mostly use this system with headphones, but currently, the Brooklyn's line-out feeds a pair of Bel Canto Design's compact e.One REF600M monoblocks driving the shelf-mounted Dynaudio Excite X14 speakers I use to play movies and videos.

My bulkier, more elaborate floor system employs a modified Home Depot rack as a totem and a variety of moderately priced cables as fetish objects. This system is not anchored by a newfangled, multipurpose device like the Mytek Brooklyn; instead, its core component is an old-school, line-level preamplifier I rely on for selecting sources, adjusting volume, and, most important, setting the entire system's gain, tone, and temper. The sound quality of every source component is affected and established by the sound quality of this single active device. Likewise, the sound character of every amp and speaker I connect to it. That is a huge audio system responsibility—so huge that most audiophiles, especially those whose only source component is a computer, are delighted to abandon separate preamps.

In my floor system I prefer to experience the texture and vivid intimacy of tubed gear—such as Rogue's RH-5 headphone amp/preamp driving their own Stereo 100 amplifier (100Wpc, KT120 tubes); or PrimaLuna's ProLogue Premium preamp driving their own ProLogue Premium amp (35Wpc, EL34 tubes). Occasionally I go all solid-state, with Pass Laboratories' HPA-1 preamp and headphone amp, and either Pass's XA25 amp or the Bel Canto e.One REF600Ms.

But what I like best of all is a tubed preamp driving a solid-state power amp. Lately, I've spent a lot of time with a PrimaLuna preamp feeding the solid-state Pass XA25. The PrimaLuna's tubes add a touch of feminine flush and glow, generating deeper reproductions of the sounds of recording venues, more distinct voices, and richer timbres—while the supertransparent Pass XA25 grips the speakers more firmly than the ProLogue Premium amp. This unusual hybrid system of tubed and solid-state separates gives Harbeth's Monitor 30.2 speakers satisfying balances of yin/yang, masculine/feminine, disegno/colorito.

Unfortunately, when I use the PrimaLuna ProLogue Premium preamp with my newly beloved First Watt SIT-3 amplifier, the sound becomes a little too flushed with second-harmonic distortion, resulting in a tiny amount of dark murkiness that's most noticeable in orchestral climaxes. This slight dullness is caused not only by the SIT-3's unusually high (for a solid-state amp) component of second-harmonic distortion (it has no feedback), but also by its unusually low gain of 11.5dB (most power amps have at least 25dB). The PrimaLuna has only 12dB of gain, which means that it and the SIT-3 provide a total gain of only 23.5dB—which leaves me about 10dB shy of a well-managed, sparkly-dynamic condition. If I use low-sensitivity speakers—eg, Harbeth P3ESRs or Magnepan .7s—this problem is exacerbated.

That was all before the Rogue RP-7 preamplifier ($4995) entered my system. In single-ended mode, the RP-7 sports 14dB of gain—only slightly more than the PrimaLuna ProLogue Premium. But unlike the PrimaLuna, the RP-7 is also a fully balanced design, in which mode it delivers 20dB of gain. That's great—but the SIT-3 has only unbalanced input jacks (RCA). However, because the RP-7 is fully balanced, I could run the HoloAudio Spring "Kitsuné Tuned Edition" Level 3 DAC (which has no volume control) into one of the RP-7's balanced inputs and pick up another 3dB of gain. Which worked quite nicely.

Best of all, the RP-7 sounded drier than the PrimaLuna. It didn't flood the First Watt with second harmonic. Like Rogue's Stereo 100 power amp, the RP-7 barely sounded as if it was running on tubes.

One of my favorite things about the Rogue RP-7 is that I can easily read its azure-tinted OLED display from 9' away. Rogue's RH-5 preamp and headphone amplifier, which I reviewed in November 2017, used a less-geezer-friendly VFD display.

The RH-5 measures 15" wide by 4" high by 13.5" deep and weighs 19 lb. The RP-7 is slightly wider, higher, and deeper—18.5" by 4.5" by 17"—and heavier, at 30 lb. It looks and feels sturdy and substantial, and, as with Rogue's Stereo 100 amplifier, the style of its steel case and thick aluminum faceplate is unaffected and timeless.

The RP-7 uses four 12AU7 dual-triode tubes and has 17 (!) separate power supplies—including an individual regulated filament supply for each tube. According to Rogue's founder and chief engineer, Mark O'Brien, the RP-7 uses military-spec circuit boards with heavy copper traces, populated with oil-filled Mundorf capacitors, Vishay resistors, and Vishay HEXFRED diodes. All of which are genuinely expensive, audiophile-certified bits.

Although bigger and wider than the RH-5's, the RP-7's front panel has the same number of buttons and knobs. The big knob at far left is the Balance control, which, late at night in the dark, I always mistake for the Volume control—which, counterintuitively, is the big knob at far right. The volume and balance knobs are stepped in increments of 0.5dB, but on the remote, balance operates in 1dB increments down to –15dB, then jumps to –90dB. This permits fine adjustment where it's most typically needed, yet facilitates the extinguishing of the channel without going through all the intermediate steps. When the Balance control is used, the OLED display shows the level of each channel separately.

Each of the nine small, round buttons strung in a row across the bottom of the front panel is topped by a little blue status LED, to make it easy to recognize and assess from afar. Close up, their tiny labels are almost legible—from left to right, Display, Proc Loop, Line 1, Line 2, Line 3, Bal 1, Bal 2, Mono (I love Mono buttons!), Power—but it doesn't matter: The display tells you, in large characters, which input is selected.

I almost never touched the RP-7's front-panel buttons—they're too high-quality and positive in their actions. I prefer the remote's cheesy plastic "lazy buttons." Unfortunately, if you want to extinguish the RP-7's bright display, you have to get up and directly push the Display button. I'd have been happier had this important feature been included on the remote. Likewise, though there's no Mute button on the front panel, the remote has one: when I hit it, a little red LED just left of the Volume knob lit up.

The chief difference between a headphone amp that includes a preamp and a preamp that includes a headphone amp is easy to spot. A proper headphone amp, such as Rogue's excellent RH-5, has separate, three-pin left and right XLR jacks, plus a four-pin XLR jack, for balanced headphone listening, and two ¼" (6.35mm) jacks for single-ended headphones. The RP-7 has only a single ¼" phone jack, and no balanced options. The owner's manual explains: "For performance reasons the headphone jack does not include a switch to break the audio signal. To mute the output from the preamp either mute the preamp or turn off your power amp."

Rogue Audio, Inc.
PO Box 1076
Brodheadsville, PA 18322
(570) 992-9901

tonykaz's picture

Azure is an expensive type of Blue, almost Lapis Lazuli. Isn't it.

For $ 5 Grand I'm wondering why they didn't use variable color LEDs like Chord would use? Maybe they're Old-School "Blue" is pricy and rare type designers.

...they sure did use "thru-hole" Circuit Boards which are far more repairable than those dam surface Mount boards which require High Magnification Surgery Tools ( and sober hands ) to repair.

"Alert & Water" as descriptives are a "First" in Audio Reviewing but "Transparent" is now Officially Worn-Out and can safely be discarded along with Carbon Fibre Record Cleaning Brushes.

Does this design present Musical Density along with it's Alertness?

Dam fine Five Star Appraisal here, bloating with exotic visuals that leave me in a Psychotic "tube rolling" wonderment.

Each HR writing is like a Sunset over the Gulf of Mexico: differing "colorings and flavorings", always beautiful and memorable .

Tony in Michigan

ps. the Audiophiliac is writing & explaining the New Rules Now.

ps. 2) Shabby Suits & used record stores in florida are Audio's version of Amish

tonykaz's picture

What is a Chinese Zippo worth?

Zippo gets it's high Value because it's Made in Pennsylvania, supported in Pa and has it's traditional value as part of American Culture. A Chinese Zippo isn't a Zippo!

A Chinese KEF isn't a Maidstone KEF made by Raymond Cooke.

A Chinese ROLEX is available at a small fraction of SWISS ROLEX Price.

Have a look at those Belgium Browning Guns and their Market Value levels compared to the Later Brownings made elsewhere.

The Market determines Prices

Chinese made stuff earns substantially lower Market acceptance.

Outfits that take their Proud Brand to Asia for Manufacture are deceiving their customer base who are not likely to remain loyal.

Asian Brands, like KIA, are building trust and Market Base thru Quality, Design and Support. KIA expanded their Manufacturing by building Cars in USA.

Asia sourcing is about TPP costing local jobs so that Corporations can avoid costs and capture significant short term profit: Quarterly.

People that support Asian Off-Sourcing do so because they've been bought ( purchased, owned ) by the Corporates, they serve Corporates not the customer.

Asian sourced stuff is worth less because it destroys it's purchaser.
It probably has negative value.

TPP is a Legacy Gift from Obama, dammit. ( My Obama )

Tony in Michigan

funambulistic's picture

Mr. Tony - who in the heck are you talking to? I would assume "Steve G." is referring to Mssr. Guttenberg, but he has nothing to do with this article, has not posted anything on Stereophile since, what June of last year and, if anything, has 2-3 posts per year (at the most). You are more likely to find him hanging around CNET or his YouTube channel, which, from what I have seen, he is very active on. I would hate for another one of your "Chinesium" tirades fail to reach your intended target because said target is not haunting the Stereophile comments section (especially comments on an article he did not pen). Good luck!

tonykaz's picture

Mr.HR's writings are read by all Reviewers, everywhere. Of course Steve G is here, reading and making contributions.

Steve G & Mr.HR are almost the same Philosophy, one is the leading man of letters and one the leading man of Visuals.

They together are Audio's Greatest Team. ( Steve & Tyll were, sadly, no more )

I'm a Stereophile participant, not a CNET. I support getting Stereophile into all Libraryies and all Barber Shops, Stereophile is the Center of the Audiophile World, Stereophile is Everyman's publication. I am a "Stereophile"!

I don't work in Publishing and am not Staff of Stereophile or connected in any way since being an AUDIO Mag. Advertiser in 1980s when I had a business relationship with L.Lovechio and Distributing Importer of HFN&RR in the 1980's.

Tony in Michigan

ps. I am a Patreon subscriber to Steve G.

grantray's picture

Maybe spend more time typing up rambling ranty stuff like this with liked-minded folks in the comments sections of Youtube or WSJ.

ok's picture

according to the "dominance/submission dialectic" the master gradually becomes more and more dependent on the servant’s mind and work, whereas the latter in turn becomes more and more potent and skillful till he finally realizes that he no longer has any use for his lazy old master – but Hegel never actually made it to our former brave new world..

tonykaz's picture

I'm feeling a rather thin understanding of your observation.

Are you suggesting "dialectic" is a debate? or investigation? or something else entirely.

English words can have too many meanings for safe usage in short technical paragraphs.

Tony in Michigan

ok's picture

since "dialectic" is actually an ancient greek term which in this particular hegelian context means "interaction" (between master and servant) or "swapping" (of economic and political power that is..)

mmole's picture

...but I always appreciate a Marxist analysis of a line-level preamp.

ok's picture

since most of the aforementioned are usually vinyl-nostalgics, in a manner of speaking :-}

The Don's picture

Why is gain important if the Sit-3 will start to clip at around 3 Volts and most preamps put out over that? Wouldn't the actual performance of the volume control be a wild card in this as most seem to work better at say 2 o'clock setting then 9 o'clock? Thanks.

grantray's picture

I saw him perform at the San Francisco Herbst Theater almost exactly two years ago. His performance of the Debussy Preludes as well as an encore of Scriabin was inspired, leaving all of us in the audience slack-jawed when the last note went silent and he stood for a final bow. It was amazing to watch his process as he paused before each piece and reflected on it before starting. He seemed to be conversing with himself on the complexity of the spirit and intent of the thing he was to create before striking the first note, in the way a visual artist pauses and prepares for the first mark on a surface. It was the kind of performance that demands a long walk afterwards. Next time he comes through New York on another tour, you should definitely go see him.

Ortofan's picture

... all that's required to produce a reference grade product for a Stereophile reviewer.

Bogolu Haranath's picture

Love (of tube sound) is blind (to measurements) :-) ...........

John Atkinson's picture
Ortofan wrote:
Apparently "generally respectable measured performance" is all that's required to produce a reference grade product for a Stereophile reviewer.

Stereophile reviewers don't see a product's measured performance until after they have written and submitted their review. So if they decide something is a reference product, this is based on their auditioning alone.

John Atkinson
Editor, Stereophile

Bogolu Haranath's picture

May be Stereophile could review the new Parasound JC-5 stereo-amp? :-) ..........

Ortofan's picture

... perhaps the reviewers should have the opportunity to make follow-on comments after they've seen the measurements. For example, would the reviewer still deem this unit to be of "reference grade" once it became known that the levels of distortion limited its resolution to only about 10 bits? Or is the effect of the added "second harmonic sauce" so beguiling that the measured performance can be ignored? If so, then why bother using such a device to listen to any hi-res (let alone CD-quality) recordings? Maybe there's an untapped market for recordings made in a 10-bit/96kHz format?

Bogolu Haranath's picture

Regarding 10-bit resolution (SNR) ......... Analog source media, vinyl and analog cassette tape have max resolution 10-bits ........ Analog reel to reel tape has max 12-bit resolution :-) .........

Bogolu Haranath's picture

BTW ..... Mp3 320 Kbps and AAC 256 Kbps have about 8-bit resolution :-) ........

ok's picture

distortion bottlenecks render any electronic “resolution” concern virtually pointless. God only knows what certain "reviewers" try to pass through their borrowed metaphors; picking up audio gear based on third party subjective accounts (and to a lesser degree on individual measurements) is in fact no different than picking up gear based on placebo, intuition or pure luck.

rt66indierock's picture

Give reviewers the measurements first then let them justify their impressions. It would be interesting to read how Herb justifies this product as reference level knowing the specifications.

Ktracho's picture

For me the question is, what is more important, to please electronic measurement equipment, or to please my ears? Also, consider that my ears don't function the same way as electronic measurement equipment. In other words, electronic measurement equipment is not a faithful model of how my ears function. Certainly, very high measured levels of distortion will be reflected by poor sound, but increasingly lower measured levels of distortion are not necessarily correlated with increasingly stellar sound. At least that's my opinion.

Ortofan's picture

... of distortion become too high to be acceptable, in your opinion?

Ktracho's picture

In my opinion, it's not a useful question. For example, how do you compare the sound of a truly great LP with a few unfortunate scratches through a great sound system vs. a cheap cell phone playing an MP3 file? More importantly, my answer would not be a useful guide for anyone else. For example, some may not be able to hear the difference between a $100 sound system and a $10000 one. Would it be foolish for someone to only spend $100 even though the distortion level in my opinion is too high?

rt66indierock's picture

This device is not quiet enough.

mememe2's picture

let's face it - unfettered love for all things with tubes.If one were to scour all of Stereophile's tubed equipment reviews( from beginning to present day) it would be hard to find many negative reviews of said equipment. Those reading should expect nothing less than approval for almost any tubed gear under review. It is what it is.