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Thursday, August 20, 2015

Audiophile Review!
Rogue Audio RP-5 Tube Stage
Line/HP/Phono Preamplifier
"New Display, Fantastic Sound!"

Brevis...
Price: $3,495 (retail)
Likes: top-tier sound, display
Dislikes: no balanced connections
Wow Factor: one of the best combo pre’s

by John Gatski
 Since the late 1990s, I have auditioned most of Rogue audio’s tube preamplifiers (and many of their amplifiers), including the original Model 88, the Athena, Hera II, Persus and the Model 99 Magnum, which I own. These hi-fi preamps are some of the best sounding and affordable tube hi-fi gear available. And they are made in the USA — Pennsylvania to be exact.
  The RP-5 is Rogue Audio’s first model using the RP-X design, an updated audio circuit/interface. “The RP-X platform is the hardware and software platform that is the basis for all new Rogue Audio preamps going forward,” explained Rogue Audio Founder/Chief Designer Mark O’Brien. “The software was all developed in house and allows us to bring much more functionality to our new designs — as well as adding features, such as the vacuum fluorescent display that we use on the RP-5.”
  O’Brien said that the RP-X allows feature sets not seen on older Rogue designs. “The ten-button remote on the RP-5 would not be possible without the new hardware and software package,” he said. “Our older preamps used a very simple controller that could only handle volume control and mute.”
The RP-5 comes in silver or all-black finish

  According to O’Brien, the RP-5 has additional sophisticated controllers that can handle many more processing tasks. “When we set out to design the RP-5, our goal was to create a vacuum tube preamp that not only sounded extraordinarily good, but included the modern feature set that our customers are looking for.
  According to Rogue Audio, the new RP-X tube circuitry is computer optimized for extreme accuracy, ultra-quiet operation and long-term reliability. “The audio circuit utilizes four 12AU7 in a mu-follower topology, which sounds terrific and barely taxes the tubes themselves,” O’Brien added. “The power supply design is one of the most critical aspects of sonic performance, and the RP-5 is based around a very large and entirely linear power supply.”
If you just consider the audiophile caliber of the line stage, the Rogue is a stellar performer and a good value. But if you throw in the separate's-quality phono and HP circuits, you got yourself one amazing preamplifier.

  As per usual Rogue Audio design, all the high-quality components used in the RP-5 are spec’d to very tight tolerances. “The coupling capacitors are Mundorf Supreme that we source directly from Germany, and the tubes are Euro-Spec long-plate versions, which we believe are the best currently in production,” O’Brien noted.

Features
  The VFD display that indicates volume, warm-up status and input is a first for Rogue Audio, whose preamps have always relied on dial legend for operational status. The RP-5 also incorporates a great sounding, tube/hybrid phono preamp section that is user adjustable, depending on cartridge. Another big plus for the RP-5 is a tube-stage headphone amp that is able to drive about any kind of headphone, and based on my listening sessions, sounded as good, or even better than many standalone esoteric HP amps, that cost as much or more than the this comprehensive RP-5 pre.
  Connection choices include four line inputs, phono input, two pairs of variable unbalanced RCA outputs, one pair of fixed unbalanced RCA outputs, processor loop, and home theater bypass. Unfortunately, there are no balanced connections.

Plenty of  inputs on the RP-5
  The attractive-looking, machined-aluminum front panel sports push button selector switches for each input, bypass and processor loop, as well as the balance adjustment and mono/stereo mode. The left-hand rotary knob controls the balance in the balance-adjust mode; the right hand rotary control adjusts the volume level. A mute LED and the headphone jack complete the front panel. The centered VFD display indicates status and volume in an easy-to-read blue hue. The full-featured remote control, mimics all the front panel functions including input selection, volume, mute, bypass mode, and processor loop engage.
  The audio circuit includes hand-select JJ 12AU7 (East European-made) vacuum tubes, high-quality caps and resistors and a massive power transformer that delivers clean AC to the RP-5 to allow it deliver modern, tube-device specs, includes a 1 Hz to 100 kHz bandwidth, plus or minus 1 dB with .1 percent distortion or less. Signal-to-noise specs were not given, but the circuit was nearly dead quiet with no signal present.

Separate-worthy phono stage
  The RP-5 contains a high-performance, tube/hybrid phono section that accommodates the majority of phono cartridges available today. It is user configurable and has adjustments for gain, capacitance and resistive loading. The RP-5 is shipped with the gain set at 45 dB and the loading factory set at 47K.
  For the more adventurous audiophile, you can remove the cover and manually adjust the settings via DIP switches to perfectly tailor the circuit to your cartridge. The two cartridge-loading switch sets (one for each channel) are located on the right-hand side of the rear circuit board, near to the phono inputs. Load setting options include 30 ohms, 50 ohms, 75 ohms, 100 ohms, 230 ohms, 300 ohms, 1Kohm and the factory setting of 47 Kohms (all DIP switches off).
 The evolutionary RP-5 adds a system processing engine for display and routing — and the classic, yet modern, tube audio path — with none of the stereotypical artifacts associated with vacuum tube designs.

  Optionally, there are two (red) slide switches to add capacitance (150pF) to the phono input. With the two switches in the down position there is no added capacitance. When the switches are in the up position 150 pF (picofarads) are added at the phono input. The RP-5 ships with these switches set to zero capacitance. (For many cartridges, the capacitance switch will not affect the sound in either setting.)
  There are also settings for phono gain. The two DIP switches for setting the gain are located on the right rear corner of the main circuit board. Phono gain setting options are: are 40 dB, 45 dB (default), 50 dB, 55 dB and 60 dB.
  The RP-5‘s dimensions are 18.5 ”W X 4.5 ”H X 14.5” D, and the unit weighs a hefty 30 pounds. In my opinion, the RP-5 is the best looking preamp Rogue Audio has ever made (love the florescent display!), and listening revealed it as one of the most accurate sounding Rogue’s as well. In fact, it is an ideal mate for the company’s flagship digital/tube hybrid Medusa amplifier — Rogue Audio’s most accurate amplifier, and one of the best-sounding hybrids available.

The set up
  The RP-5 came along at a good time; I had not sent back the warm and wonderfully open Pass Xs-150 super Class A MOSFET amplifier, and I had a slew of new hi-res music, a bunch of DACs, a VPI turntable and, of course, my MartinLogan Montis electrostatic speakers to project all my music.
  The associated equipment included an Oppo BDP-105 universal player, ASUS ME572C Android tablet/player (using USB Audio Player Pro USB DAC player software), Benchmark DAC2-DX D/A. Mytek Manhattan D/A, VPI Scout 1.1 turntable with a Benz-Micro L0.4 Wood MC cartridge, and a TASCAM DA-3000 professional/audiophile PCM/DSD player.
  Speakers included the aforementioned MartinLogan Montis speakers, as well as a pair of Legacy Studio, Paradigm Prestige 15B and Westlake Lc8.1 small monitors — placed on stands. Amplifiers auditioned: the exquisite Xs-150's (a 2014 EAN Luxury Class Audio award winner), Bryston 14-B SST, Rogue Audio Medusa and my old classic Macintosh MC275, circa 1965. (many men have tried, many men have failed to pry it from my 6550-blistered fingers).


The RP-5's fluorescent display is a first for Rogue Audio


  All analog/digital and speaker cables were courtesy of Wireworld; power cables, except when I inserted two pairs of Darwin Cables low-dielectric analog line cables between the Mytek DAC-to-RP-5 input and the RP-5 output-to-Rogue Audio Medusa input. All IEC-receptacle components were connected to the AC via Essential Sound Products Essence II power cables plugged into the Essence II power strip.
  After a three day break-in of letting the RP-5 play in the background with a test tone CD, I commenced the subjective listening. Upon engaging the RP-5‘s power-on button, the first thing you notice is the delayed start-up and the corresponding display 40 second countdown, “40, 39, 38, 37...” with no audio until you hear the relay click. Then you are ready to listen.

The audition
  A premium preamp deserves premium music to listen to, so my first demo was my own home-studio recorded, 24 bit/384 kHz sample rate, stereo recording of a Taylor 810 acoustic guitar that I made with a high-end Antelope USB A/D and Audix SCX-25B microphones. The advantage of recording your own hi-res music is that you cut out the middle man; no multitrack overdubs, countless edits and tuning with EQ, etc. This cut was made direct from the mics, mic preamps, the A/D straight into the Macbook Pro. The A/D high-res capability captured a detailed, involving acoustic guitar tone — with extensive detail and pick harmonics being captured through the system.
  A really good playback system makes the little demo that I recorded in 2013 jaw dropping. Played through the ASUS tablet via USB Audio Player Pro, which plays up to 24/384, I connected it to the the Oppo HA-1 DAC and used the the RP-5 and the Rogue Medusa hybrid for the analog playback stage, passing the signal on to the MartinLogan Montis electrostatics.
Premium parts and a tidy layout inside the RP-5

  On playback, the Rogue RP-5/Medusa rendered the guitar cut with a crisp, focused detail with a stereo spread that seemed a mile wide. The tube preamp playback motif may connote a warm, rounding of the overtones and harmonics, but the actual playback shows how modern this Rogue tube circuit is. The guitar’s pick plucks, reverb tails and intricate "in-between-the-string" sonic spatial cues were amazingly accurate — like the best of solid state, but with a superb analog smoothness. And in the quiet guitar parts, I heard no tube noise, circuit noise, etc.
  I played the home-brew guitar cut several times with the Pass Xs-150 amps in the system as well, and the separation and image detail was even more impressive, though a bit warmer sounding than the Medusa. Overall, My first playback session with the Rogue RP-5 was was rated grade A.
  I switched the format to jazz,and popped in my Warren BernhardtSo Real SACD, recorded in 2000 by Tom Jung at DMP. This minimalist, direct-to-DSD recording features piano, bass, and drums. The recording features one of the most accurate capture of a Steinway grand piano I have ever heard. A serious audiophile system can relay the piano’a complex, upper-register harmonics to a live-like portrayal as you will ever hear. On lesser system, a bit of that complete liveness disappears. I am happy to say that the RP-5 handled those ultra-fine piano tones with ease, as well as the openness of drum cymbals. The title cut particularly stood out.
The RP-5 relays the finesse of "Stairway To Heaven" as well as $10,000 preamps I have auditioned. It is just musically right right with no omissions, or tonal additives that spoil the music’s essence.

  Moving on to Classical music, I popped in the RCA Red Seal reissue of Brahms' Violin Concerto In D Op.77, as played by Jasca Heifetz and the Chicago Symphony OrchestraThough originally from an analog tape recording, the performance of Brahms violin concerto is my favorite in terms of the “masters” performance. And the recording system captured much of the Stradivarius violin’s, rich, bow-to-string detail that can be heard through really good components — like the RP-5. 
  I sampled a variety of Pop/Rock hi-res through the RP-5 including Jason Mraz Love Is Just A Four Letter Word (24/96), all the 24/96 remastered Led Zeppelin re-releases and the download 24/96 remaster of Michael JacksonOff The Wall from 1979. I also played some recent remasters of country music’s golden age, including Waylon JenningsHonky Tonk Heroes (24/96), Willie NelsonThe Sound In Your Mind (24/96) and Dwight YoakumGuitars, Cadillacs, etc., (24/96).
  With Pop/Rock music, the RP-5 kept it all together, sounding clean, open and dynamic — with no midbass bloom or heard edged midrange. The acoustic guitar intro on Jason Mraz’s — “I Won’t Give Up” is as expressive and focused as I have ever heard it. Michael Jackson’s “Rock With You” from the remastered Off The Wall shows off the rhythm guitar with a wider stance and prominence than on previous versions, and the RP-5 brings it home in all its analog funkiness.
  No matter how many time you have heard Zeppelin’s “Stairway To Heaven” and you think you know every nuance of its sonic signature, the recent remasters showcase the classic in a wider, detailed, smoother character, especially the intro acoustic guitar, flute solos and clean electric rhythm guitar. The RP-5 relays the finesse of "Stairway..." as well as $10,000 preamps I have auditioned with this music. It is just musically right right with no omissions, or tonal additives that spoil the music’s essence.
  As for the RP5‘s tube/hybrid phono section, it is an excellent clean, tube phono pre that gives the end user a lot of latitude in tuning for a particular cartridge. Playing a mix of new and old audiophile LPs through the VPI/Benz Micro L.04 MC cartridge, I found the 47K setting optimized the system pretty well.
The RP-5 HP stage handled the dynamics of the “Time Flies” track as well as several high-end separate HP amps I have auditioned. And versus many of the onboard DAC HP amps, I thought it’s stereo image capability a bit more spacious.

  First up was the Beethoven Sonatas Nos. 8 And 10 (180-gram Mono Vinyl Limited Edition), originally a RCA Red Seal LP. This 1953 Jasca Heifetz/Emanuel Bay violin/piano recording is one of the best mono classical performances I have ever heard — with abundant detail revealed from the piano and vivid violin performance. And despite the pre-noise reduction era of this recording, surprisingly little hiss.
  The Benz Micro L0.4 MC's signature is very accurate, without midbass bloom and mid brightness, yet the ultimate high end is very resolved with this recording. The Rogue phono preamp did a fine job projecting the nuance of the Steinway and Stradivarius instruments’ harmonics— creating a full stereo image from just one mic.
  I did not hear any vintage “tubiness” through the RP-5 — especially in the bass; the piano’s lower register was spot on. The hybrid design keeps the low end fast and clean. For a combo preamp's phono stage housed in a full-featured preamp, the Rogue RP-5’s phono circuit sure is worthy of separate status.
  I was equally impressed listening to my classic original audiophile pressing of The Isao Suzuki Trio/Quartet - Blow Up. This piano, drums, and bass cello Jazz recording (1973 - Three Blind Mice) never ceases to impress my ears, and the RP-5 handled all the tracks just fine. The key to accurate, involving playback is getting the album's dynamic, rich cello and drum cymbal detail improper balance, which the Benz/VPI combo can accomplish. The RP-5 just passes on that turntable’s playback of each cut — nothing added/nothing taken away. I listened to the LP five times. Could not get enough — like the perfect glass of Malbec.
  I had one Rogue Audio preamp on hand for comparison, the Model 99 Magnum, so I thought I would compare preamp’s audio signatures. To my ears, the Model 99 has always had the most classic defined tube tone of the Rogue preamps, due to the 6SN7-utilized design. It has a warm, up-front soundstage with ample detail. Compared to the RP-5, however, the ultimate detail, width and precision bass tone comes from the newer preamp. From an accuracy standpoint with hi-res, the RP-5 excels. The ’99 is a quality, classic tube preamp with a nice optional phono stage, but give me an RP-5 for the 24-bit and DSD.

A dandy headphone amp
  Since I had plenty of headphone amps on hand for comparison, I did quite a bit listening through the RP-5’s HP circuit. As with its line-output, the tube headphone stage was excellent; neutral timbre, quick, tight bass with plenty of musical detail. Excellent depth and width to the stereo presentation.
  I spent a full day listening to Classical and Jazz music via the Rogue headphone amp with the Oppo PM-1 planar magnetic headphones; Also tried out my AKG K702 Anniversary and Shure SRH-1840s. Listening to the Anthony Wilson TrioOur Gang Jazz SACD (jazz guitar, drums, Hammond organ) through a pair of Oppo PM-1 planar magnetic headphones, the RP-5 HP stage handled the dynamics of the “Time Flies” track as well as several high-end separate HP amps I have auditioned. And versus many of the onboard DAC HP amps I have heard, I thought it’s stereo image capability a bit more spacious. The warm, slightly overdriven, Hammond tone-wheel organ sounded gorgeous via the RP-5 HP output.
Euro-Spec 12AU7's are quiet and linear in the RP-5

  I really was tickled by the sound of jazz guitar via the RP-5. A stand-out track was the vocal/guitar accompaniment “Days of Wine and Roses,” from the Joe Pass/Ella Fitzgerald 24/88 download of Easy Living. All my HPs sounded high-end with this track — with Pass' warm Gibson ES-175 signature and EF's velvety vocals. By the way, with the headphones, you can really hear how quiet the hand-selected tubes are.

The verdict
  Overall, the Rogue Audio RP-5 design and ultimate performance is what I expected from a Mark O’Brien design, who always is at the top of his game when a new Rogue product goes into design  The evolutionary RP-5 adds a system processing engine for for display and routing — and the classic, yet modern, tube audio path — with none of the stereotypical artifacts associated with vacuum tube designs. The only quibble I have is no balanced I/O, but I am sure you will see that feature in a future iteration.
  Although I have heard nearly all the Rogue preamps, the RP-5 quickly became one of my favorites. In fact, because of its smooth transparency, I began to rely on it for all kinds of reference listening. It is that good. If you just consider the audiophile caliber of the line stage, the Rogue is a stellar performer and a good value. But if you throw in the separate's-quality phono and HP circuits, you got yourself one amazing preamplifier. Another Everything Audio Network Stellar Sound Award for Rogue Audio!

  John Gatski has been evaluating consumer, audiophile, home cinema and professional audio gear since 1988. In 1995, he created Pro Audio Review, and he has written for Audio, Laserviews, Enjoy The Music, The Audiophile Voice, High Performance Review Radio World and TV Technology. Everything Audio Network is based in Kensington, Md. Articles on this site are the copyright of the ©Everything Audio Network. Any unauthorized use, via print or Internet, without written permission is prohibited. John Gatski can be reached via everything.audio@verizon.net 








  

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