Prism Orpheus Digital Interface

Prism Orpheus Digital Interface

A long and winding road leads to this review. The road is by no means smooth and straight, bumping along with disappointing gear and side trips to failed technologies. The road is an analogy for this writer’s audiophile journey, which currently finds us in a very nice place thanks to the Prism Orpheus Digital Interface. About 18 months ago, I was introduced to the convenience of iTunes and was very interested in finding out for myself if the current digital technology would allow me to convert my aging and slowly deteriorating collection of vinyl LPs to a digital format that would be as enjoyable as listening to records.

Prism Orpheus Digital InterfaceI started this “digital conversion side trip” with a MacBook and an Apogee Duet ($500). The Duet is a portable analog-to-digital (A-D) and digital-to-analog (D-A) converter that offers 24 bit 96 kHz recording and playback over a Firewire connection to a Macintosh host computer. This combination sounded very good and brought the playback of CDs to a new level, in some ways surpassing the very expensive CD players I had been listening to. But as a replacement for LPs? Not good enough. So I replaced the Duet with an Apogee Rosetta 200 ($2000), which is a Mac and Windows-compatible 24 bit 192 kHz A-D/D-A converter, again making use of the pro-standard Firewire connection. This was certainly an improvement in the D-A section, delivering a level of musical clarity that largely eliminates the artificial electronic digital signature found in most CDs. The Rosetta 200 also clearly demonstrated that the 192 kHz sampling rate is a large improvement over 96 kHz during the A-D recording of LPs. The sound quality of this combination is on par with SACD. However, there was still a fairly deep divide between the enjoyment of listening to LPs versus their digital counterparts. Even so, digital sound was getting better.

A 20” iMac replaced the MacBook due to excessive noise from the notebook’s cooling fan. Both Macs sound the same. I enjoyed the little Mac remote control, but since I am a long-time Windows user – I upgraded from Windows version 3.1 to version 3.11 in the early 1980s just to have Bitstream fonts - I felt more comfortable with a Windows platform. That operating system upgrade required eleven floppy disks. I can’t image the technology we’ll see in 2050.

About this time, I began to evaluate music playback and recording software on the iMac and on a Windows XP computer. I obtained very good performance from Windows XP on a PC with a modest 2.4 GHz Pentium 4 processor and 2 GB RAM, suggesting that a high-powered PC is not required. While iTunes sounded good on the Mac OS X, it was noticeably inferior on the Windows operating system, sounding thin and coarse. I tried a lengthy list of music management software and felt like Goldilocks looking for a comfortable bed. Too many features, too few, hard to use, ugly user interface, poor sound quality, etc. Add/Remove Programs was selected many times.

I finally settled on JRiver Media Center and continue to use it on a purpose-built Windows 7 computer. This computer has an Intel DG45ID motherboard, Intel E8400 Core2Duo processor, 4GB memory, Seagate 1TB hard drive, and a Pyro 64R2 PCI Firewire card with Texas Instruments chipset (very important), all housed in the very-quiet Antec NSK 2480 case. Next to the listening seat is a small Virco 8771 adjustable table with a 20" LCD monitor, a wired compact keyboard and a Logitech LX-7 cordless mouse. There is a 1.5TB external USB hard drive for backups and I back up often. You should, too! (Please see image below). This is the digital audio workstation, or DAW for short.

The Apogee Rosetta 200 on Windows 7 sounds very good. But even at 24 bit 192 kHz, this combination was not an acceptable replacement for LPs and after finding no suitable high-end audio components, I continued to look at the gear the pros use to record music in their studios. Brands like Lavry, Benchmark (also reviewed here on 10 Audio), M-Audio, Weiss, and Lynx became familiar names. I scoured the discussions on pro message boards like gearslutz.com. The result of this research led to the Prism brand of digital converters. Prism holds an almost cult-like respect among those who use this type of gear for a living. You may think that audiophiles are the only people who test, evaluate, A-B, and tweak gear for better sound, but the much larger population in the pro-audio world can make some of our efforts look a little puny.

Other components used during the review period included Marantz MA-9S2 Reference Series monophonic amplifiers, YG Acoustics Kipod Main Modules and Dali Euphonia RS3 stand mounted loudspeakers, JL Audio f112 and Velodyne Optimum-12 subwoofers, SOTA Cosmos IV turntable with TriPlanar VII u2 tonearm and Miyajima Shilabe phono cartridge, and Sonic Frontiers Line 2 SE+, Audio Research LS26 and Marantz SC-7S2 preamplifiers. A vacuum tube Manley Steelhead phono preamplifier has served as a reference for over two years. A Sansui TU-717 tuner provides a line-level source for breaking in new components and for background music. Interconnects are Mogami balanced and RCA, with Element Apollo and Audience Au24e loudspeaker cables. Power products included a PS Audio PowerPlant Premier, Audience PowerChord e, my DIY power cords and power conditioner, and Element Stealth "es" and PS Audio PerfectWave AC-10 powercords.

Prism makes separate A-D and D-A converters, each with price tags over $10,000, which are used in some of the best recording studios in the world. The Prism Orpheus carries a list price of $4,500. Discounts are rare and resale prices are high. Prism converters were used by Abbey Road Studios during the recent remastering of Beatles music. Grammy award winner Frank Filipetti used an Orpheus to record Carly Simon. Prism ADA-8 converters played a key role in recordings from Diana Krall, Willie Nelson, and Barbra Streisand. According to some users, the Orpheus meets or may even exceed the sonic performance of the costly separate converters. So I bought one. To call it a digital converter is like calling the nuclear-powered aircraft carrier U.S.S. Enterprise a “boat”. This simplistic term doesn’t begin to relate all of the possible ways this immensely capable ship can be used. The Orpheus is:Prism Orpheus Volume Control
- An analog-to-digital converter
- A digital-to-analog converter, with 2 Firewire connections, and S/PDIF on RCA and Toslink
- An 8 channel balanced preamp with 8 balanced outputs
- A studio quality mixer, with a front-panel volume control
- A digital upsampler and sample rate converter
- A headphone amplifier, supporting 2 headphones with individual volume controls
- A master clock for other digital components
- And lastly … are you ready for this? ... a high quality RIAA phono cartridge preamplifier with up to 65dB of gain and a THD+N of 0.00028% (-111dB).

Let’s look at that last feature. The gain is adjustable in 1 dB steps from 10 dB to 65 dB of gain. These fine adjustments are useful for setting the proper recording levels. The input impedance is fixed at 1 megOhm. I found that these Instrument inputs become noisy above about 45 dB of gain in my system with a cable connected or even when these inputs are shorted, so I question the THD+N spec above. That issue, plus the non-optimal loading for a moving coil phono cartridge of 1 megOhm suggests the use of an outboard moving coil step-up transformer. I had great results from a Bob’s Devices step-up, and finally made one using Sowter 1990z transformers with OCC wire and the very expensive (and dead quiet) Texas Components TX2575 .01% resistors to set the proper load. Upon entering the Orpheus through the unbalanced Instrument inputs (used for phono), microphone inputs, or line-level inputs, all audio is converted to digital and all further signal processing, routing, and gain occurs in the digital domain.

Before talking about the sound, I think it is important to mention how easy it was to install the Orpheus in my typical home stereo system. Well, friends, installation was not easy at all and was about as far from plug-and-play as you can imagine. In fact, I didn’t even get sound the first evening of learning – and fiddling, and experimenting, and cursing – the software interface. First, the unit required a firmware upgrade and updated software for the computer to recognize the presence of a connection to the Instrument inputs. These were not difficult to rectify and should now be present in any Orpheus which you might acquire. Second, the two front panel mono Instrument input connections and all of the balanced outputs use ¼” plugs, TS (tip-sleeve) for the former and TRS (tip-ring-sleeve) for the latter. You will need to use adapters, have your cables re-terminated, or buy new interconnect cables to use the Orpheus. So instead of plugging in my interconnect cables and popping in a CD, I plugged in my soldering iron and whipped up appropriate interconnects using Mogami cable and Neutrik connectors. And third, the software, while extremely flexible, is based on a professional mixing console, not on your typical stereo preamplifier. Sliders (in software) instead of knobs, icons instead of buttons, and three different panels with Input, Output, and Mixer settings, some of which are interrelated and need to be set correctly or else you get zilch from your speakers. The initial learning curve, unless you already understand pro gear, is steep.

Prism Orpheus Rear Panel

Of course, most of this initial pain was caused by my lack of knowledge and experience. I received some very good advice which helped immensely: RTFM. Like most audiophiles, i.e. men, I don’t ask for directions and I don’t read the owner’s manual - unless I get zilch from my speakers! So having solved these minor issues, I heard something on the second evening.

And it was not very good. Used only as a phono preamplifier with the Bob's Devices step-up transformers for additional gain and proper cartridge loading, at first the Orpheus sounded harsh and thin. This is typical of a new digital component. So I plugged my tuner into the Instrument inputs for two weeks of non-stop line-level break-in which turned out to be essential for good sound. After about 300 hours of break-in, the sound quality improved dramatically. My reference phono stage is the excellent Manley Steelhead, an older version 1 unit which I purchased from EveAnna Manley (thank you again!) and have thoroughly enjoyed listening to for a couple of years. The first thing I noticed about the Orpheus was how similar it sounds to the vacuum tube Steelhead. Sweet, detailed, and 3-dimensional. Over several more hours and days and weeks of listening the differences between these two vastly different technologies became apparent.

The Orpheus has great extension and resolution in the treble. This is the one area that I expected some harsh “digititis” to rear its ugly head and become both obvious and annoying: a real deal breaker. But on repeated listening – analytically and critically, over weeks and months – I became convinced that the upper frequency performance of the Orpheus is truly excellent. The sound of triangles is pure and sweet with a harmonic trail that fades into black without changing character on the way up in frequency and down in volume. Cymbals are presented with their metallic sheen intact and a captivating sense of real metal vibrating in front of me. It is important to note that all of these observations are at 24 bit 192 kHz resolution. It is not that any lesser sampling rate loses significant objective quality, but 192 kHz is clearly better, having much less of a sense of listening to a recording and far greater ability to forget the electronics and simply enjoy listing to music.

-- Orpheus installed in my audio rack with moving-coil step-up transformer:
Prism Orpheus Installation

The Orpheus “multi-function audio Swiss army knife” is dynamic. Bank on it! In amplifiers, this ability is often quantified with the slew-rate specification, or how fast the device can deliver instantaneous increases in volume. The Orpheus has no noticeable limitation in its dynamic presentation. Both huge thunderous explosions and barely audible tap-tap-taps on a cymbal are presented cleanly. The well defined leading edge of every sound - in the bass, in the midrange, and in the treble - makes all music accessible, engaging and very lifelike. Unlimited headroom is also found in nature.

There is a bit less warmth and roundness in the midrange compared to the Steelhead on an absolute scale, but with a slightly increased level of texture and low level resolution. It is not really fair to say one device is better or worse than the other; character is often like that! Spend a few days with the Steelhead or with the Orpheus and either one will sound correct and put a smile on your face.

Continuing with the comparison, the Prism presents more details in the upper treble, making the Steelhead sound relatively soft and rolled off. This detail is real resolution, not a trick of hyped or grainy upper frequencies. The Orpheus’ bass is closer to excellent solid-state sound, powerful and detailed with excellent reach into the lowest bass. The differences in the virtual sound stages are also noticeable. The Steelhead has slightly better depth and all of the recording spaces seem larger, even when the recording was made in a studio. The Orpheus has a bit better placement of instruments left-to-right across the stage, allowing individual musicians and singers to stand out in sharper relief from adjacent performers. Again, the characters of these two excellent units, used as phono preamplifiers, makes themselves known in short order, but a simple judgment of superiority is elusive. However, lately I find that I have been using the Orpheus for LP playback more often. Similarly, I prefer LP recording using the Prism's built-in RIAA filter instead of plugging the turntable into the Steelhead.

Let’s talk about CD playback. I had been listening to the Cary 306 Professional and Marantz SA-7S1 SACD/CD players when this side trip started with the MacBook/Apogee Duet. As I mentioned above, this computer based “CD player” brought me closer to the music than the more conventional players in many ways. One important thing that the Cary and Marantz units brought to my listening room was an appreciation for the large differences in musical quality afforded by different sampling rates. With the Orpheus, it was easy to zero in on the optimum settings for LP and CD. Nothing less than 24/192 resolution on the Orpheus offers “LP Replacement Quality™” sound for LP recording and playback. There are more options for playing standard 16 bit 44.1 kHz CDs. With the Cary and all successive experiments in up sampling, only whole number multiples of 44.1 kHz, i.e. 88.2 or 176.4 kHz, offered improvements in sound quality. Try to interpolate CDs at 96 k or even 192 kHz, and it just sounds wrong. A musically discordant “phasey” quality with an almost subliminal sense of artificial and annoying high frequency artifacts becomes apparent in short order. But up sampled at 176.4 kHz…

View from listening seatCDs can be a real high resolution medium capable of long term musical enjoyment. I have not spent much time with SACD, but with both the Cary and Marantz players I appreciated that format’s significant increase in sound quality over CD. SACD does not provide quite the level of musical communication and immersion as listening to LPs does, but with the lower noise floor and lack of clicks and pops, SACDs perform at a level that I could probably live with on a long term basis. When CDs are upsampled to either 88.2 or 176.4 kHz their sound quality improves significantly. Through the Orpheus, CDs played back at the 176.4 kHz sampling rate are as enjoyable and convincing as SACD. The overall sound quality is quite similar to LPs recorded and played back at 24 bit 44.1 (and maybe 96) kHz resolution, and that is saying a great deal about the exceptional quality of sound from the Orpheus D-A converters as used via the Firewire input. Mac (Core Audio) and PC (ASIO, WDM, WASAPI) compatible.

All music has a wonderful feeling of natural flow and coherence across the octaves. Curiously absent while listening to the Orpheus are the analytical distinctions between the sound of the bass and midrange and treble. The sound just flows up and down the audible frequency range with no highlighting, forwardness, or other emphasis in any particular frequency range. And with this flat frequency response is a perfectly linear "resolution response", offering a constant tonal quality across the entire audio spectrum.

As a line-level preamplifier, the Orpheus is hard to fault. I do not say this to imply that the sound is perfect, however. I can listen to the Orpheus through a preamplifier and then bypass that preamp by plugging the Orpheus’ outputs directly into the power amps. It is then easy to hear how the preamp affects the sound. But how do you bypass a direct connection? Listening to better 24/192 recordings, or playing LPs in real time using the Orpheus as both a RIAA phono preamplifier and line stage preamplifier direct into the power amplifiers, I prefer the direct sound to that from a “regular” preamp. The sound is clearer, more immediate, less obscured, and the performers are more lifelike and believable. However, with most CDs or less than excellent LP digital transfers, I occasionally prefer to listen through a good, clean and neutral sounding tubed preamp like the Line 2 SE+. Sure, this flavors the sound a bit, but that spice seems to offset the small deficiencies of the music source files in a positive way.

The overall construction quality is excellent, except that the system volume knob feels wobbly and not up to the solid and professional feel of the rest of the unit. Two different Orpheus units were involved in this review. Strange behavior during recording was observed with the first unit and it took a while to localize the problem as a hardware issue. Technical support from the factory was excellent during this period. The second unit has operated perfectly since it was first installed several months ago.

I would love to see a choice of software for this very capable unit. The pro-oriented interface works well after it is understood, but it would increase the market potential to offer software that resembled a conventional stereo/multi-channel “hi-fi” preamplifier rather than a pro-sound mixer. That would cut the learning curve tremendously and make the daily use of the Orpheus much less intimidating. (For example, you could easily destroy your speakers by forgetting to lock the volume control and then deselecting VOL on the Output Setup panel while music is playing.) However, if you use it only one way, as a DAC, for example, you could make all the settings in software and then close the software control panel forever. The Orpheus remembers its last configuration.

At this point, you may be thinking that installing and using this unit in your system would be more trouble that it is worth. And you would be wrong. Allowances, both financial and practical, must be made to use this professional studio processor in a home audio system. The results would be well worth the effort, especially now that your expectations have been properly set.

It would be easy to write a lot more about this unit because it does so many things and can be used in other ways, and also share with you some more observations from this audio side trip, which, by the way, is now a permanent change of direction thanks to the Prism Orpheus. For example, I have not tried it as a DAC using a coax digital input, which would be the input of choice in many installations. And for recording LPs, the free Audacity software and the Orpheus' built in RIAA filter sounds better than using Pure Vinyl software and its own software RIAA. And the audio quality of higher bit-rate Internet "radio", up sampled to 24 bit 192 kHz resolution, is very good and makes it difficult to justify having a component FM tuner. And finally (for now), a stereo system could consist of a computer with Internet access (to stream any of hundreds of on-line "radio stations" and probably your favorite FM station, too), a Prism Orpheus, an amplifier and speakers. With the Orpheus successfully installed, a line-stage preamplifier, phono preamplifier, tuner and CD player are all redundant.

Prism Orpheus

The Prism Orpheus is several reference level components in one compact enclosure and is certainly a tremendous value. Whether used as a line level preamplifier, RIAA phono preamplifier, A-D or D-A converter, sample rate converter or upsampler - or any combination of these, the Orpheus offers excellent sound quality that easily passes our Zen Test.

Technology is moving forward continuously and it is certain that the overall performance of the Orpheus will be bettered, and sooner rather than later. At this time, I know of nothing else in the marketplace that can be considered as competition. The Prism Orpheus Digital Interface offers LP Replacement Quality™ sound and earns 10 Audio's highest rating.

Overall Rating: 10 LPs

10 Audio 'Perfect 10 Award'

Link to manufacturer's Web site: Prism Sound