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Thursday, September 14, 2017

Audiophile Review!
Raven Audio Osprey
Integrated Tube Amplifier:
“A Modern/Classic 6L6 Valve Amp”


Brevis...
Price $4,595
Likes: classic tube tone, attractive look
Dislikes: a little bit pricey for 30 watts
Wow Factor: perfect for stand speakers
More info: Raven Audio Osprey


by John Gatski
  Tube hi-fi amplifiers never go out of favor, and even today, they come in a plethora of configurations, sizes and power levels. I have listened to countless tube amps over the last 25 years from Rogue Audio’s finest to old Macs and Marantz's — and everything in between.
  Newcomer Raven Audio, manufactured in Texas is emerging as a player in the tube amp niche with a number of nice amps that pay homage to the old days, but also offer modern features, such as remote, IEC power cord and auto bias.
  Case in point is the $4,595, manufactured in USA, 30-watt Raven Audio Osprey, an amp that reminds you of the early 1960s integrateds with its open-chassis, prominent front-mounted tubes and covered transformers.
  Via a 6L6 push-pull output circuit, the Osprey puts out an ample 30-watts per channel CLASS AB. Its tube complement also includes a 12AT7 - 2EA for the preamplifier stage, 12AT7 - 2EA for the power amp first stage and a 12AU7 - 2EA - phase inverter/driver.

Features
  The Osprey’s build quality is exemplary with tidy circuit boards, chassis made out of carbon steel (main cabinet) and aircraft-grade aluminum (faceplate and preamplifier tube plate). The handles are manufactured out of solid aluminum, and the knobs are machined out of aircraft-grade aluminum as well. Overall, the Osprey is an attractive amp that should please the eyes of any hi-fi enthusiast. It comes in two colors: jade and pearl white. I had several audiophiles over when I had the jade amp in demo, and they commented how cool it looked.


  Like old Mac MC30s, the Raven Osprey is perfect for stand speakers; the Legacy Studio HDs and the Amphions really shined  — with a spot-on bass/treble balance and a golden, sparkling top end.

  Besides the 6L6GC output tube complement, supplied with Russian-made tubes, the Osprey receives the royal treatment in internal parts including RavenCap – Silver Foil; PTFE high-quality audio capacitors and Alps Black Motorized 20 k ohm volume potentiometer.
  The amp is housed in a partial, open-chassis (tube) and an enclosed compartment for the power transformers located in the rear. The front controls are simply laid out on the front panel: power knob, volume control and source selector.
  As far as the circuit, the Class A/B auto-biased system is designed to work with  the 6L6GC spec tubes. The auto bias take care of the bias, as long as the tubes are matched quads.


Easy connection and plenty of them


  Raven President Dave Thomson said the amp is designed for 6L6 (G, B or A) output tubes as well 5881 or KT 66s —  even 7581As for a "little extra kick." Older 6l6WBT tubes, however, are not recommended because of the higher plate voltage required by the tube.
  The back panel contains six pairs of unbalanced RCA inputs, and 4 and 8 ohm speaker binding posts. The IEC power cord is a bonafide 14 gauge wire made in France.
  From a design standpoint, the Raven Osprey is a modern update of the classic 6l6GC design of say the old Mac amps of the early 1960s. Tube watts often seem fuller and louder than solid state watts, and the Osprey has got plenty of oomph with just 30 watts. Thomson said Osprey is a “highly souped-up, highly customized, much more powerful version of the company's Blackhawk LE Integrated.” All Raven amps are made in Trinity, Texas

The set up
  I installed the Raven Audio Osprey in my primary audiophile room, and plenty of different speakers were on hand for testing with the tube amp. Raven says the amp performs best with speakers with 90 db+ sensitivity, though I drove the MartinLogans with no problem, though their powered sub means the Osprey saw a lighter bottom-end load.
  Speakers included my MartinLogan Montis, a pair of Legacy Studio HD’s, Westlake LC8.1s and a pair of the Finland-produced Amphion. All of the latter speakers are nearfield,  stand speakers.
  Source gear included Oppo BDP-205 universal player, and several DACs: the  Oppo Sonica DAC, Benchmark DAC3 HGC and Mytek BrooklynI also auditioned the Osprey for LP record playback, utilizing a Parasound Zphono with a VPI Player TT and Hanna high-output moving coil.
  Wireworld Eclipse cables were used for speakers, analog and digital connections. Essential Sound Products Essence Pro II power cables, power strip connected the components to the AC.

The audition
  To get a sense of the Osprey's stereo imaging and transient impressions, I first hooked to the MartinLogan Montis. Since the bass is handled inside the Montis via a self powered acoustic suspension 10-inch woofer, the Osprey was not driving below 300 Hz. But it allowed me to first hear how the tube amp handles the critical midrange and treble.
  Playing the DMP SACD of Steve Davis  — Thought About You, which has fantastic percussion. I found the Osprey’s top end to be warm, yet seductive. It relayed the brash cymbal splash with that pleasing tube smoothness. Not quite as fast as say my Pass XA-30 Class MOSFET amp, but I thoroughly enjoyed the tone.

Raven amp assembly at U.S. factory

  And, by the way, the Osprey did the MLs proud. The imaging is huge via the dipole electrostatics, and the amp does a nice job putting the sonic info across the speaker plane.
  As good as the supplied tubes sounded, I popped in a matched set of Yugoslav-manufactured JJ 6L6GCs and found that the Osprey became even more transient rich and slightly faster on cymbals, pianos and such. I liked the increased accuracy I heard with that tube complement.
  On the Joshua BellTchaikovsky: Violin Concerto in D SACD, the JJ tubes opened up the harmonics on the violin versus the factory-made tubes more velvety signature. I liked the amp with those JJ tubes, but I also tried a 1990s matched quad of Svetlana 6L6GCs, which had an identical tone to the JJ’s.
  With the top end sounding pretty darn good, I switched off to a set of Pass SR-1, three-way towers with the amp now driving the entire speaker. Though not the most sensitive of transducers, the Pass speaker ramped up to a loud enough level, if required, But more importantly, it showed that the Osprey's bass performance was quite good.
  The Raven’s bass was full, but not slow through the Pass towers, and the upper end was musically smooth with strong dimension to 5 kHz and above. The Pass tower speakers revealed that the Osprey had a classic tube tonality and balance but with good dynamics.

Perfect for stand speakers
  The best balance of sound I got out of the Osprey was with stand speakers, such as the Westlake LC8.1 (8-inch woofer/1-inch tweeter), Legacy Studio HD (6-inch woofer/ribbon tweeter) and the Amphion Argon3S (5-inch woofer, 1-inch tweeter).
  Like old Mac MC30s, the Raven Osprey is perfect for stand speakers; the Legacy Studio HDs and the Amphions really shined  — with a spot-on bass/treble balance and a golden, sparkling top end.
  The Tuck and PattiWith Love CD from 2003 is a beautifully mic’d vocal and guitar recording that showcases Patty's complex vocal tones, while Tuck’s modified Gibson L5 jazz guitar plays incredible solo and rhythm runs that are so fleshed out and full. The CD, as played through the Osprey and Legacy Studio HDs, was very musical to use a well worn phrase. That voice/guitar cohesion shined via the Raven — with a slight rounding of the percussive guitar picking that made it easy to listen to.
  On the Amphion Argon3S’s, I liked my tried and true audiophile test tracks. The title track from the Warren BernhardtSo Real SACD. As mentioned many times in my reviews, the drum cymbal recording is among the best I have ever heard. The Amphions are very accurate little speakers, and the Osprey pushes through the essence of the brushes and snare rim shots with a slightly reserved character that fits the speaker perfectly.

 Although there are plenty of tube amps out there that range in prices from the hundreds to the many thousands of dollars, the Raven Audio Osprey is a good choice for a low-powered, tube integrated for small-room listening. Vinyl fans, hi-res audio aficionados and those who just like the glow of the valve, will like this amp.

  The Westlake LC8.1’s really stood out when playing the limited LP release of The Isao Suzuki QuartetBlow Up, a 1970s audiophile Jazz LP favorite that consists of upright bass, drums and piano, re-released a few years ago in a half speed, special vinyl. The treble-rich, analog tape source recording, as played via the bang-for-the-buck Hana cartridge and VPI Player TT, hit its stride with the Osprey. The Westlake's soft-dome tweeter ease on cymbals and bright piano textures helped to balance it all out.
  And the Osprey’s spacious stereo width and depth, with the 6L6’s warmth intact, was readily apparent. The Parasound phono pre is not expensive, but it did a  fine job with the Hana cartridge and a great sounding record.
  On harder, denser Pop music and heavy Rock, I am not always a fan of vintage tube amp tone. It can sound really mushed on lesser amps. But the Osprey surprised me on some older, analog-sourced Rock and Roll.
  The 24/192 remaster of NirvanaIn Utero sounded surprisingly detailed and fleshed out, considering all the electric "fuzz" from Kurt Cobain’s guitar. Classic Black Sabbath in 24/96 (Vol. 4, for example,) also was not as thick as I thought it would be through the Osprey. Tony Inomi's Gibson guitar riffs and rock hard solos kicked butt.
  Classic country music revealed an ear-friendly richness via the Osprey. Waylon JenningsHonky Tonk Heroes 24/96 RCA reissue (from HDtracks), for example, really sounded good through the Osprey/Legacy Studio HD tandem. Ralph Mooney’s edgy steel guitar gets tamed a bit via the tube stage, making it more listenable at higher levels. Love that jangle of Waylon's Telecaster.

Trying different tubes
  I should point out that Raven sent me a bunch of extra signal tubes, vintage NOS including Telefunkens, etc. I did not think they made as much difference as did switching output tubes. In my opinion, when a properly designed, signal tube is mated to the proper circuit, even a Chinese tube can sound good. I usually judge signal tubes by how noisy they are. The supplied tubes were pretty quite and, thus, I was happy.


The pearl white Osprey

  Raven President Dave Thomson does believe that different tubes can have a subtle effect on the tone, and he is a big fan of NOS USA and European tubes. He recommends experimenting with various brands of signal tubes. “Feel free to experiment and depending on your speakers, the cables, etc. you will be able to find something that you like better than all others.”
  Regarding his penchant for seeking out the perfect tube, Thomson added: “And this is one of the main reasons tube amps are so darn much fun!”
  Overall, I had no problems with the Raven Audio Osprey, no extraneous noises, excessive hiss or hum. Once I dialed in my choice for output tubes, I was golden. The remote control worked perfectly, it was easy to connect banana plug speaker cables, and, most importantly,  the Osprey had a musical charm when sitting down to listen — just like my original mid-1960s Macintosh MC275.

The verdict
  Though there are plenty of tube amps out there that range in prices from the hundreds to the many thousands of dollars, the Raven Audio Osprey is a good choice for a low-powered, tube integrated for small-room listening. Vinyl fans, hi-res audio aficionados and those who just like the glow of the valve, will like this amp.


  It ain’t cheap at nearly $4,600, but it is a fine stereo tube integrated amplifier, nonetheless, that looks as good as it sounds. Because of its combination of tube sonics, user versatility, attractive appearance and USA build, EAN is giving it a Stellar Sound Award.

   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 email: everything.audio@verizon.net

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