|Reviewer: Les Turoczi
Digital sources: Naim CD2; Modwright Sony 999ES Signature Truth Mod; Sony PCM R500 DAT deck; Sound Devices 744T HD Digital Recorder
Analog Source: Linn Sondek LP 12 fully upgraded with Lingo, Cirkus, Trampolin etc.; Naim ARO arm; Spectral MC IIB and Denon 103 [naked] cartridge; ARC PH3SE phono stage; Magnum Dynalab Etude FM tuner
Preamp: Audio Research REF 1 line stage
Power Amp: McCormack DNA 500 for mids and highs; two Electron Kinetics Eagle 400 monoblocks on woofer systems
Speakers: Zu Definition Pro
Equalizer: Rane PEQ55 parametric equalizer for low bass drivers only [<40Hz]
Cables/Wires: Interconnects, speaker wires and power cords all from Zu Cable
Power: Dedicated power line; BPT BP-3.5 Signature Plus balanced power conditioner
Accessories: Symposium Svelte Shelves and Fat Padz; "The Base" platforms; Walker Audio Extreme SST Silver Treatment and Reference HDL Mk. II links; Sound Organization racks
Room size: 14' by 23' with 8' ceiling, speakers set up on short wall; carpeted concrete flooring
Review component retail: $2,700
Over time, the phrase straight wire with gain has surfaced in an attempt to describe an elusive ideal, namely the pristine purity and accuracy of different forms of audio gear without recognizable sonic signature. Famous designer Stu Hegeman -- whom I had the pleasure of meeting when I was still a pup -- is often credited with this phrase when talking about amplification circuits. It still crops up in reviews and essays about sound. The question remains - are we any closer to this particular ideal today?
As circuit implementations undertook more or less diverse paths, broad variations in sonic signatures, component flexibility, pricing and complexity arose. My own Audio Research REF 1 tubed line stage certainly demonstrates an intricate approach toward striving for a fine balance between accuracy, transparency and the ever-ephemeral "musicality" as well as it could in its heyday. In contrast to its level of complexity, a number of passive line stages have come about. While they appear in different configurations from wiper attenuators to resistor ladders and beyond, the transformer-based volume control has stepped into the spotlight ever since Thorsten Loesch collaborated with Stevens & Billington to reintroduce the commercial parts necessary to author one [S&B's part is now in Gen. III, SAC?Thailand just introduced its own Supermalloy version and autoformers too are employed for such purposes- Ed.] . Let's see how the so-called TVC fares against a tubed active that was well regarded in its time.
The Chinese-built Opera Consonance Ref 1.3 line stage is well constructed and has a solid feel coupled to unusual but appealing looks. Steve Monte, the US importer/distributor at Quest for Sound, sent the unit a few months ago and it proved easy to install. My system is biamplified, so after getting the appropriate Zu cabling to interface with the McCormack DNA500 amp for the mids and highs and the Rane PEQ55 bass equalizer, which feeds the Eagle 400 monoblocks for my speakers' rear-firing bass arrays, it was fun from the start and enjoyable music flowed.
If the concepts associated with transformer volume controls are new to you, I recommend the excellent treatment Srajan provided in his review of the Music First Audio TVC. Without repeating most of his content, suffice it to say that transformer volume controls handle gain attenuation in a way that minimizes impedance mismatching and other weaknesses associated with conventional resistive passives. This Consonance unit uses a 20 position switch which allows the two multi-tapped miniature transformers to control volume. I first became attuned to the TVC concept last autumn when audio pal David visited and brought his kit-built Bent Audio TX102. My prior experience with passives hadn't been terribly positive so the skeptic in me was on high alert about this general approach. David's gear put those reservations in question and I was sorry to only have it in my system for that one long day of his visit. Obviously, my appetite had been whetted to investigate transformer volume controls further. Fortunately the arrival of today's review piece helped to make the particular strenghts of such technology clearer to me.
The change from my ARC REF1 line stage (which carried a retail list price of $8,500 when new over six years ago) to the Consonance Ref1.3 was very instructive. For one thing, power cord concerns fell by the wayside. Secondly, there was very little to fiddle with other than to ascertain the influence of the switched volume control, which thankfully did nothing more than cut gain - it was sonically invisible. There is no remote control, not a big hassle but my personal preferences do lean toward inclusion of that feature as a normal expectation. [An S&B-based passive with full remote control will shortly be introduced for others like Les who want that feature - Ed.] All connections including a mix of XLR and RCA jacks were easy to establish and the initial sound generated in my listening room was quite good. The unit weighs in at 22 lbs. and that heft feels solid, uncluttered and welcomed. Dimensions are about 17" wide x 6 ?" deep x 4" high and the wood-covered top is carefully finished, adding an unusual but attractive visual touch. Interior views reveal a simple but clean layout of parts and high attention to detail.
Out of habit, I let the Consonance Ref1.3 play continuously for several days, using the FM tuner primarily but not exclusively as a means of burn-in. I don't think there was any major difference from day one to day five but not knowing how much time this particular piece had on it before it came to me, I made this effort. Next, running through several of the CDs typically employed for critical evaluation, I was enthused to find a style of sound that reminded me of the excellent experience encountered earlier with David's TX102 TVC with its Gen II S&B transformers. I could not directly ascertain the manufacturer of the transformers in the Consonance unit except that they're not from S&B. A fair guess would be that they're of Chinese origin. In broad terms, the sound was effortless, smooth, rich and engaging. I went back to my tubed REF1 for comparison and felt that the Consonance offered better high frequency extension but a touch less bloom and spatial depth. One twist that did help the passive was placement on three Symposium Acoustics Fat Padz footers. The unit had already been sitting on a Symposium Svelte Shelf but now with the Fat Padz as the mechanical interface, things became more focused and tighter. I kept this configuration for the balance of the evaluation period. Quest for Sound does offer their own relatively inexpensive versions of stratified cork and rubber footers but I preferred the Symposium combination.
The range of music I use for both critical and pleasure listening is wide. It encompasses large orchestral pieces from well-known discs generated by Reference Recordings, Telarc and a few other small but well-respected labels. Jazz recordings such as Kind of Blue, Keith Jarrett discs, Ella, Pat Metheny and Diana Krall along with a few other notable standards cover small ensembles. Classic and some newer rock music were not ignored either. My own recordings of acoustic live classical performances certainly figure strongly in how I judge things but that won't help most of you since they are private recordings in the hands of the performers and a few audio buddies/music fans only. Most audiophile friends who have heard those discs like them for their natural and uncluttered presentation, which is a principal goal for me as a recordist. Being in the audience near my microphone stands has done much to fine-tune my hearing at both the concert settings and during subsequent playback at home. Vinyl spinning was part of the evaluation process in addition to the silver disc library. While this did not dominate my listening sessions, a goodly number of LPs were heard and that experience confirmed all of the impressions garnered from CD and FM. This is mentioned to merely denote that a broad spectrum of musical genres, performers and formats is always employed in my evaluations and reviews. I try to cover all bases.
The ability of the Consonance Ref1.3 to deliver clear, balanced and engaging music was obvious from the start. The amount of attenuation provided was certainly in the same ball park as my active ARC line stage so getting volume levels needed for meaningful and customary listening requirements was a non-issue. Tweaking via isolation footers etc. merely refined what was already a strong and positive sonic signature. Instruments, whether from large orchestral sections or solo work, always felt timbrally intact and correct and had a sense of completeness and integrity. In the past I've heard certain audio components that were transient intense where ferocious attack abilities rendered the body of instruments or voices anemic and threadbare. Not so the Ref1.3. Ambience retrieval was very good, with a bit more lateral spread than depth. My ARC REF1 did convey depth of field more emphatically but there are those who believe that tube gear can hype this parameter. When I attend live concerts I hear depth depending on my seat location in the hall so for me the way the ARC line stage delivers that effect just feels preferable. The Consonance was no slouch in this department, however. [The debate over how much depth is accurate really varies a lot with your location, venue properties, performers and a host of other details; it is almost meaningless to get overly entangled in that issue.] Bass extension from the Consonance was authoritative and in excellent proportion to everything else. As a pipe organ fan, this does matter to me. Notably, the lowest octave over this TVC was a touch deeper and tighter than I was accustomed to with the active ARC. It made me wish that the REF1 was better at this performance aspect. The TVC's midrange was unstrained, smooth and without any obvious problems. From very detailed recordings I determined that transparency and resolution were portrayed in a straightforward manner, with no major differences compared to my usual expectations. All in all, the sonics delivered by the Ref1.3 TVC felt really good and inviting. But the story gets more interesting.
An intriguing opportunity arose from an email exchange I had with Srajan about TVCs in general. He wondered if I would consider trying the Music First Audio Passive Magnetic Attenuator [which he reviewed quite positively] as a contrast to and context for the Consonance. I liked that idea and Music First's then US distributor started the ball rolling so I was able to do the side-by-side testing.
The $2,995 Music First Audio TVC is smaller and more compact but otherwise sports similar connectivity bundled into a clean, well-made package. It's famous for employing the very highly regarded Stevens and Billington transformers from the UK and MF Audio in fact is an S&B subsidiary. I let it settle for about five days, mimicking the process employed for the Consonance. Once more the comparison against my ARC REF1 gave me pause. The Music First unit did most things in very similar ways to the Consonance, albeit with a few twists. For one thing, the Fat Padz beneath the Music First did not make any significant difference. A better approach resulted from placing an old standby VPI Brick on the top panel of the metal case. Not a big difference but a bit more focus. The Music First conveyed a deeper soundstage and also appeared to have a tad more transparency than the Consonance. Instruments tended to float in space more readily and the top octave felt even more extended now.
Barring such a direct comparison, I would not have sensed anything amiss listening to the Consonance alone. The Ref1.3 was doing a very good job with the important kinds of sonic characteristics needed to make the music happen. There clearly were more similarities than differences between these two passives. My impression is that the Consonance is slightly warmer so if the listener prefers a more rounded presentation, it would be a fine choice. This factor may be valuable for those with systems that tend to be on the bright side of neutrality. Naturally, the Music First might serve better in a component array where the sound could benefit from a bit of airiness. There are arguments, left and right, about seeking out neutral components so as to not depend on any one device as a tone control against its neighbors. In an ideal world, that makes sense. In the real world, however, we are always making adjustments or refinements to balance off sonic properties or preferences. Each of these two TVCs is able to yield excellent music portrayals, with the opportunity to customize in one direction or the other based on how the associated co-joined elements and components coalesce. In my system, I could be happy with either TVC but I'd give a slight nod to the Music First unit. It synergizes nicely with the biases and desires at work in my listening room. Synergy is key here. Ignoring that side of life could be problematic if not downright foolish. I know several systems at friends' homes where I'd bet dollars-to-donuts that the Consonance piece would fit best. Incidentally, the 6dB of step-up gain available on each unit were unnecessary and I used volume control settings around 12 o'clock during regular -- non-bombastic -- listening sessions to mirror the REF 1.
The looming question of how TVCs impacted my long-term habit of listening through active line stages does deserve attention. Over the years, I've owned and enjoyed several different preamps and line stages, including the now ancient ARC SP3A, Jeff Rowland's delicious Consummate and most recently, the oft-noted ARC REF1 just to name a few. This history did briefly include two very different simple passive attenuators but that was about seven to eight years ago. While cable length and compatibility were not issues for those passives then, I came away feeling that a level of richness, spatial rendering and coherence were just not part of their configuration and design implementation. A sense of sonic sterility bothered me in those approaches to passive attenuation. Tubes, on the other hand, provided listening experiences which added a great deal of pleasure to music reproduction. This was true for the bulk of the time when I occupied my easy chair particularly for the sheer enjoyment of music, not for when the reviewer's hat was in place. Of course, the added variable of facing or denying the challenge of tube rolling and replacements comes into play actually more often than I would like.
As other owners of valved gear know, I found exotic tubes -- both NOS and newly minted ones -- which could deliver certain qualities but not others. For instance, I remember a marvelous set of NOS Amperex that possessed fine musicality but suffered from excessive microphonics. Another set of them did just the opposite. Oy! Multiple attempts to get all of this in balance caused lots of frustration. Even with my 'best pick' tubes most recently fitted to the REF1, tiny amounts of tube hiss, electron rush or very miniscule amounts of hum still get on my nerves over particular recordings. Any of these TVCs in my system helped those noise issues to just plain disappear. I found no loss in transparency, texture or richness when comparing the TVCs to the ARC line stage. I can restate that the sense of bloom from orchestras and large ensembles does feel stronger with tubes, especially on live acoustic music recorded in sonically large and good spaces. Studio and close-mic'd recordings are less obvious for this parameter. While I enjoy that blossomed sense of things, one could speculate over whether it is fully accurate. The familiar call of tubes does occasionally sing out to me not unlike the Sirens enticing Odysseus. My response to that call remains uncrystallized. For context, I must note that there are two newer generations of ARC's Reference linestages, the REF2 and REF3. Neither have been in my system. A whetted appetite is a strong force. I will need to explore things a bit further before reaching absolute clarity.
In closing, I am really pleased that the world of transformer volume attenuators came to my attention. Whether the ideal of a straight wire with(out) gain has been attained or not, the ability to understand and access the music, the musician's intent and the emotion behind it all is closer now than it was for me previously with the active preamp. The Consonance Ref1.3 comes across as a fine and competent audio component, bearing good looks and flexibility coupled to high performance and a reasonable price tag. With all of the other well-received products emerging from the Opera stable of gear, the Ref1.3 TVC adds glowingly to the successes of this manufacturer and I'm happy to recommend it for serious auditioning. Anyone looking for a simple but effective approach to completely quiet line stage designs would do well to include the Consonance Ref1.3 on their short list of contenders.