Rogue Audio Hydra Hybrid Power Amplifier Review 
Home Theater Power Amplifiers Stereo Amplifiers
Written by Andre Marc   
Thursday, 31 May 2012

I have had a fondness for Rogue Audio’s products since I reviewed the Atlas Magnum power amp a while back. I recently reviewed the Perseus Magnum preamplifier.  Rogue products remind of classic muscle cars that came out of Detroit in the 1960’s. Ballsy, well made with pride, and very distinctly American.

Rogue’s products are also a great counterpoint to those audiophiles who complain about no “affordable” high performance components being made in the U.S.A. They often use this excuse to purchase products made in Asia, essentially rewarding manufacturers who take their operations overseas. One look at the Rogue price list on their website and you can see just how affordable their entry point products are. They also have a proven track record of longevity, great customer service, and accessibility.

Rogue is well known for their tubed electronics, which makes the product under review here an eye opener. I received a sample of the brand new Hydra hybrid power amplifier. What kind of hybrid?  A tube and Class D solid state design. This is fascinating for a number of reasons. First, Class D designs have been around from a number of years, but have never been “approved” by purists who complained of flat sounding and uninvolving earlier generations. They were, however, praised for bass performance and other virtues, such as efficiency.

Class D designs have some distinct ergonomic advantages. They are very efficient, run cool, and what you would call “green” amplifiers. Attitudes towards Class D designs have changed recently, with companies like Audio Research, Mark Levinson, bel canto, and Cary Audio bringing Class D products to market. Of course several companies like NuForce, and Channel Islands Audio made their names exclusively selling Class D amps.

To break it down rather simply, a Class D, or ‘switching”, amplifier is based on a high-efficiency circuit designed to boost the power of incoming signals. Its operating principle is very different from other amplifier classes, abruptly switching its output transistors either completely on or off.  The benefits, as stated above (high efficiency, bass, etc), have made them easy choices for many active speakers, powered subwoofers, and Home Theater setups.

Obviously, Mark O’Brien of Rogue Audio saw some unused potential in switching amplifiers and has decided to blend tubes, Rogue Audio’s forte, with this new technology. For the particulars of the design process for the Hydra, and its big sister, the Medusa, see this fascinating and informative O'Brien interview.

Now for the particulars. The Hydra offers up 100 wpc into 8 ohms, and 200 wpc into 4 ohms.  It retails for $2995. For comparisons sake, the Medusa doubles the power and retails for $3995. The amp features two 12AU7 tubes, high quality binding posts, XLR and RCA input jacks, and a custom machined silver faceplate that is classic Rogue. The build quality is typical Rogue too. That is, if anything, it is overbuilt!

Set Up & Listening:

Setting up the Hydra was a breeze. I used a Transparent AC Cord and drove it with my Audio Research SP16 tubed preamp, connected my Transparent speaker cable, and then let the soft circuit startup do its thing. When stabilized, which takes about thirty seconds, the LED on the front panel goes from amber to blue.  Speakers were my reference Thiel CS2.4’s. I let the Hydra burn in for about five days before doing any critical listening.

Rogue Hydra Power Amp

To cut to the chase, this is a superb amplifier. The key words that came to mind were transparent, dynamic, controlled, and effortless. All the virtues of a really good solid-state amp, and none of the drawbacks. The Hydra was extremely transparent to sources, but served the music first. Forget all your preconceived notions, if you have any, about Class D amplifiers. Rogue has found a way to make it work. Having tubes in the signal path is just a brilliant idea, and obviously contributes much of the pristine qualities I heard.

I called upon a wide variety of music that I have been recently using to evaluate gear to put the Hydra through its paces. First up was Home Again, the debut from British neo folk/soul singer songwriter Michael Kiwanuka.  He reminds me greatly of a modern Richie Havens, Van Morrison, or Tim Hardin. His album even has a vintage feel, with tape saturation and classic reverb splashes. The album features Kiwanuka’s acoustic guitar, flute, some orchestration, and his soulful voice. The lead-off track, “Tell Me A Tale”, has a great live ensemble feel, very much like Morrison’s Astral Weeks album. Through the Hydra I was able to “see” deep into the room and hear the space, fabricated or not, around all the instruments.  There was a great sense of rhythm and drive.

My pick for one of the very best albums of last year is Ray Lamontagne's sublime God Willin & The Creek Don’t Rise. Not only is the music of the highest artistic order, but it is superbly recorded as well. It is rare to hear a batch of such incredible songs on one record these days, but Lamontagne pulls it off. The title track, “Beg, Steal, or Borrow", “This Love Is Over”, and “New York City Is Killing Me” are ones for the ages. The Hydra was able to connect to the music, provide superb texture and imaging to the sublime arrangements, and beautifully frame Lamontagne's otherworldly voice.

Little Broken Hearts, the devastating new album by Norah Jones, is also well recorded and, interestingly, produced by Danger Mouse. The opening track, “Good Morning”, is a densely layered lullaby that builds and swirls around Jones’s voice. The Hydra untangled all the complex layering easily. The second track, “Say Goodbye”, features a persistent, catchy bass line, multi-tracked vocals and, again, the Hydra provided all the drive and nuance needed to embed this song in my head for weeks on end.

About three quarters of the way into the review period, I installed the Hydra in my second system, driving Harbeth Compact 7ES3 speakers. I used the Belles Soloist 3 preamp, connected via Transparent interconnects, with a Squeezebox Touch, Marantz CD player, and a Lindemann DAC as my sources. The Hydra fit right in and gelled beautifully in this system. It brought a pristine clarity and transparency as it had in my main system.  As a matter of fact, it made my Harbeth’s come alive, producing a soundstage width and bass quality I have not yet heard in this room.

One of my favorite recent jazz albums is Quartet by legendary guitarist Pat Metheny and piano genius Brad Mehldhou.  The Hydra delivered the full richness of this excellent recording, with the opening track, “A Night Away” simply dazzling with its texture, rhythm, and drive.  A bit more understated, but no less captivating, is the 96/24 download of Diana Krall’s When I Look In Your Eyes. The opening track, "Let’s Face The Music And Dance”, was simply stunning in its elegance, and flow.  Her all acoustic band had a gorgeous, woody texture, and her voice was beautifully rendered.

In operation, the Hydra was utterly noiseless, ran cool (except for some heat directly over the area where the tubes are installed), and proved to be 100% reliable. All Rogue products come with a solid warranty, which should give any potential buyer peace of mind. Not that I would worry. My experience with Rogue products is that they keep on trucking.


Rogue Audio Hydra Hybrid Power Amplifier

There is rarely anything new and, for that matter, exciting these days in high-end audio outside of computer audio, which is spreading like wildfire.  However, every once in a while a new product raises an eyebrow and commands some investigation. The Rogue Hydra and its larger sister, the Medusa, are such products. There have been reported cases of Class D amplification and tubes being used in the same circuit before, but I don’t believe any have come to market from a legitimate company like Rogue.

In my opinion, this hybrid experiment, if you can call it that, is a smashing success. But to be clear, it probably took all of Rogue’s engineering knowhow to pull it off. And pull it off they did. They obviously designed the circuit well, but all the other classic amplifier parts were chosen carefully and engineered into the equation. Couple that with superb build quality and a product that is made in the U.S.A. and you have a recipe for success.

I can unconditionally recommend the Rogue Hydra amplifier. Tried as I did, I could not hear any sonic flaws normally associated with older Class D designs. There was no trace of flatness, treble edge, solid-state haze, or any such related issues. On the contrary, there was richness, openness, and an overall refined air to the sound. The only caveat I can offer is that, while the Hydra will have no trouble driving any speaker, matching is important (as with any amplifier type). Other than that, I would suggest opening your mind and ears and give the Hydra a go. At just under $3000, the Rogue Hydra represents a tremendous value like most, if not all, Rogue products.


Rogue Audio Hydra: $2995
- Output power: 100/200 WPC 8/4 Ohms
- Input impedance: 200K Ohms
- dimensions: 18" W x 15" D x 5.5" H
- weight:Hydra 34 lbs

Review System 1

CD Transport: Musical Fidelity M1 CDT
Server: Squeezebox Touch w/ CIA VDC-SB power supply
via Ethernet to MAC Mini w/ Western Digital & Seagate
external drives.
DAC: Bryston BDA-1
Headphone Amp: Pro-Ject Head Box II
Headphones: Grado SR60
Preamp: Audio Research SP16
Amplifier: Audio Research VS55
Speaker: Thiel CS2.4
Cables:  Stager Silver Solids, Kimber KCTG (IC), Transparent  MM2 Super (IC), Transparent Plus (Speaker) Acoustic Zen Tsunami II (AC),Transparent (AC).Shunyata Venom (AC) Element Cable Red Storm (Digital AC), DH Labs TosLink, DH Labs AES/EBU
Accessories: Symposium Rollerblocks, Shakti Stone, Audience Adept Response aR6 power conditioner,Salamander rack

Review System 2

CD Player: Marantz 5003
Music Server: Squeezebox Touch via Ethernet to
MAC Mini w/ Western Digital & Seagate external drives.
DAC: Musical Fidelity V-DAC II, Lindemann USB 192 DAC
Integrated Amplifier: McIntosh MA6600
Tape Deck: Revox A77
Speaker: Harbeth Compact 7ES3
Cables: Kimber Hero HB, DH Labs White Lightning (IC),QED Genisis Silver Spiral (Speaker),PS Audio (AC), Pangea Audio (AC), DH Labs TosLink, Audioquest Forest USB, Wireworld Ultraviolet USB
Accessories:Cable Pro Noisetrapper, Sound Anchors Stands, Wiremold AC Strip

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