Rogue Audio RP-7 line preamplifier Page 2

At the left of its rear panel, the RH-5 had an optional RCA phono input. In contrast, the RP-7 has line-level inputs only. At the left of its rear panel are eight black XLR jacks: two pairs of balanced (MOSFET-buffered) outputs and two pairs of balanced inputs. These dark XLRs are followed by a regiment of bright gold RCA jacks: two unbalanced outputs, a unity gain input, a processor loop, a fixed output, and three line-level inputs. Happily, this arrangement gives me up to five line-level sources. Very nice. Stacked at far right are the main power rocker, a fuse bay, and a three-pronged IEC power-cord inlet.

The RP-7 includes a 30-second soft start with auto mute, to go easy on the tubes and suppress turn-on transients.

Listening with the First Watt amps
The HoloAudio Spring DAC driving the Rogue RP-7 driving the First Watt SIT-3 power amp driving the 93dB-sensitive DeVore Fidelity Orangutan O/93 speakers created a superbly balanced and invigorating—nay, intoxicating—system that didn't sound like tubes or solid-state. But it did reproduce, with extraordinary weight and saturated tones, my latest favorite piano album: Alexander Melnikov performing Debussy's Préludes, Book 2, then joined by Olga Pashchenko in Debussy's own four-hands arrangement of La Mer, all performed on an 1885 Érard piano like the one Debussy used when composing the Préludes (24-bit/96kHz FLAC, Harmonia Mundi/Qobuz). This exotic album is all about the sound of a vintage piano. Its purpose is to show the listener how richly toned and expressive these old, less tightly strung instruments can sound. The playing of Melnikov and Pashchenko isn't lacking in feeling or poetic insight, but the intent of this recording is to present what Debussy must have heard while working on these compositions. Through the RP-7, note attacks were arousing. Note decays were extended. Pedaling was psychedelic. Tone was full-spectrum and saturated.


After my experiences with the First Watt SIT-3, which has only single-ended inputs (RCA), I felt a need to try the RP-7's balanced XLR outputs. I connected another First Watt amp, the J2 (25Wpc into 8 ohms, $4000), which accepts balanced inputs and is a pure made-in-heaven match for Harbeth's Monitor 30.2 speakers ($6495/pair).

When John Atkinson measured the M30.2s for my review of them in the April 2018 issue, he estimated their sensitivity at 87.3dB(B)/2.83V/m—which, he said, "is usefully higher than the specified 85dB." The M30.2's impedance remains above 6 ohms throughout the audioband. As a result, the Harbeths sound rich, lively, and articulate with the First Watt J2. Most important, the Rogue RP-7 kept a cool, steady hand on the J2. This combo of preamp, amp, and speakers made beautiful sounds: saturated tone, never too hard or too soft, never too warm, never stressed or compressed. My only dilemma was which music I should listen to next. Pleasurable.

Now the sound of Melnikov and Pashchenko playing Debussy reminded me of aged French brandy: It had a sensuous, mood-enhancing flavor that lingered, inspiring reverie. Suave and sophisticated.

The bass frequencies on Pat Metheny and Charlie Haden's Beyond the Missouri Sky (Short Stories) (24/96 FLAC, Verve/Qobuz) sounded slightly digital-artificial, but the RP-7 plus J2 made the Harbeth M30.2s sound deeper and fuller in the lower octaves than I'd thought possible. Haden's bass work was just-right tight, and his instrument was almost full height. The added reverb surrounding Metheny's guitar fashioned a dreamy, intoxicating mix with pulsing illusions of a vast dark space. This combination of gear and recording generated the kind of pure beauty of sound that, for me, makes being an audiophile a rewarding enterprise.

In fact, this combo of tubed preamp and solid-state amp sounded so enjoyably sophisticated that I'm compelled to include one more supreme listening experience. Anyone who thinks digital is more truthful or lifelike than analog has never owned a Koetsu Rosewood Signature Platinum moving-coil cartridge, and has definitely never experienced the vivid analog reality of the Purcell Consort, under the direction of Grayston Burgess, in Now Make We Merthe: Medieval Carols (LP, Argo ZRG 526). I know this 1967 LP intimately; it showcases stunning three-dimensional sound in the service of great but humble human art and seasonal merriment. I've heard it through countless systems, some with preamps costing six times the RP-7's price, but none has put me in closer, more intimate touch with these ancient Christmas songs sung by the Boys of All Saints, Margaret Street. With the Tavish Design Adagio phono preamp added to the system, I played this record on a wet, cold December night, my apartment lit only by beeswax candles. I wish you could have been there to sense the purity of space and tone. This delightful mix of Rogue tubes, Koetsu magic, and First Watt silicon put my mind near a Christmas choir singing in a stone church.

I know this system is not inexpensive, but to my taste, it played up there with the very best I've heard.

Listening with the Bel Canto Design monoblocks
Connecting the RP-7 to Bel Canto's e.One REF600Ms showed me how low in so-called tube coloration this Rogue actually was.

The REF600M's input impedance is 200k ohms in balanced mode, 100k ohms in single-ended. Therefore, it mated comfortably with the RP-7's MOSFET-buffered output impedance of 50 ohms, balanced.

When I used the RP-7 and REF600Ms to play the Debussy piano recording, I was surprised at how dark and nontransparent it sounded—not thick or slow, just slightly dark-gray opaque. I doubt this was caused by the Rogue, which all along had sounded cool-air crisp and water-clear with every other amp in the house. I was expecting the Bel Cantos to produce more light and air, more of a sense of openness—but I got less. To its credit and my pleasure, the Rogue–Bel Canto pairing did an excellent job of reproducing the weight and impact of acoustic pianos and pipe organs.

Listening with the Rogue Stereo 100
But Rogue's best preamp didn't need to pass those other tests. It needed only to do a perfect job of driving Rogue's own 100Wpc power amplifier, the Stereo 100. Which it did.

The first song I played, via the Harbeth M30.2s, was "I'm So Glad," from Skip James's well-recorded (ca 1964) comeback album, Blues from the Delta (16/44.1 FLAC, Vanguard/Qobuz). It sounded so good that it jumped out and smacked me down, and made me feel a little bad for praising those other amps as much as I had. That first track with the Stereo 100 was an instant wow moment. This preamp-amp-speaker ensemble sounded so startlingly present, so absolutely clear, so completely undistorted, that I sat there laughing and shaking my head. What's that corny old audiophile line? "Veils were lifted!" In this case, it felt like all the veils were gone. James's ethereal voice, his guitar and piano, were laid bare, blatantly there.

You say you want a revolution
Well, you know
We all want to change the world

Next I played The Beatles (aka the White Album), and remembered what had led me to this Rogue combo in the first place. While reviewing Harbeth's Monitor 30.2, I'd realized that this medium-size stand-mounted model would make a perfect, neutrally balanced reference speaker. But I needed just the right amp—one with more horsepower than my Line Magnetic, PrimaLuna, First Watt, or Pass Labs could provide. Now, while listening through the RP-7 to Giles Martin's remix of The Beatles in this 50th Anniversary Edition (2 LPs, Apple B0028831-01), I felt completely validated in my decision to choose Rogue's Stereo 100. The sound was transparent, insightful, and extraordinarily alive. I had almost no criticisms of it.

Take this brother
may it serve you well

Listening through headphones If you came of age with the Beatles, as I did, I humbly suggest that you listen to "Revolution 9," from The Beatles, from start to finish, through audiophile-quality headphones—say, Sony's overachieving MDR-Z1Rs, Audeze's lively LCD-Xes, HiFiMan's state-of-the-art, planar-magnetic Susvaras, or JPS Labs' revelatory Abyss AB-1266 Phis. Any of those revealing transducers will show you everything your big speakers don't.

The RP-7's headphone amp and Giles Martin's remix showed me gobs of what I'd never known this incomparable classic contained—but the Rogue's headphone output also tainted "Revolution 9" with rolled-off high frequencies that made it sound dull, and with more noise than I find acceptable. The noise seemed like a 120Hz ground-plane problem. It was worst with the 103dB-sensitive LCD-Xes, least noticeable with the 83dB-insensitive HiFiMan Susvaras.

Rogue Audio's RP-7 line preamplifier is definitely a Herb Product—how could it not be? It's built like a farm tractor, and looks unpretentious and timeless. It sounded remarkably uncolored—to its great credit, the RP-7 walked the narrow path between tube sound and transistor sound. It was dynamic. It delivered exceptional transparency along with extraordinary weight and body. It played with a relaxed, organic tone enhanced by only the slightest touch of burnished tube glow. Alert and water clear are the most apt descriptors. My new reference.

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.