Jeff Rowland Design Group Coherence preamplifier & Cadence phono stage Page 3

Following the RIAA stage, a very robust INA-103 instrumentation amplifier buffers the unit's output and allows the Cadence to drive long lines and capacitive loads with relative ease. The Cadence can be powered by the second output on the Coherence's battery power supply, or can be bought as a standalone unit with either its own battery or an AC-only supply.

A sonic reference
The credo to which any top-drawer preamplifier must aspire is also of paramount importance to me as a reviewer and music lover: First, do no harm. While no preamp I've evaluated is truly transparent, a few at the upper end of the quality scale come close—and not all of them cost a small fortune. Without a doubt, though, the Coherence and Cadence are solid members of this elite class.

Sonic differences can be heard even among the best preamps, yet it's all too easy to exaggerate such differences when describing what often amount to subtle shifts of timbre, dynamic shading, transparency, and image perspective between otherwise top-tier products. When evaluating products that strive for genuine neutrality and are solidly engineered—such as the Coherence and Cadence—it's also easy to attribute qualities to the preamp that properly belong to other components or variables in the record/playback chain. Ironically, there's often more to say about the sound of those models—some of them very costly—that use subtle colorations for euphonic appeal, and about second-class products in which budget restrictions place an audible cap on performance.

My impressions of the Coherence apply in full to the Cadence as well. However, the Cadence made its own mark as easily the quietest and most dynamic phono stage I've heard. Indeed, with my ear to the tweeter and no material being played, it was as quiet as my digital processor! This fact is all the more impressive because much of Honolulu, where I live, is notorious for strong RFI/EMI fields. In my experience, the Coherence/Cadence rig took the brass ring as the most consistent performers in their class, particularly in such tough environments.

Good bypass tests can ferret out and confirm subtle variations between competing products, while adding a critical measure of proportion that helps tether one's perspective to terra firma. In this case, I achieved a healthy 86dB SPL at my listening chair by directly connecting the 2V output of a Muse Model 296 24-bit/96kHz processor to the active crossover of my Audio Artistry Beethoven Grand speakers. After repeated listening to familiar tracks, the preamps under test were reinserted and precisely matched to the direct digital source, with only a short interconnect as a second variable. This technique eliminates the attenuator and/or impedance variations possible when using a passive line controller, or a CD player with built-in volume control, as a "bypass" setup.

Under such scrutiny most preamps quickly reveal a loss in transparency, shifts in image perspective and/or focus, and masking of low-level harmonic decay. Poorer models even show evident timbral colorations and a blunting of the leading edges of transients. That said, it's surprising just how small in scale these anomalies are among the better preamps I've auditioned.

There was a very faint loss in transparency when the Coherence was added to the chain during these tests, and though I easily heard extremely fine levels of decay detail through the preamp, the direct bypass mode made subtle decay characteristics slightly more immediate. However, it took multiple attempts to sort out these variations with certainty, and resolution of the leading edges of transients and harmonic timbres remained remarkably consistent with that of the direct sound, varying only with a small increase in smoothness and the richness of broadband timbre with the Coherence in the system. However, the big surprise—and a first for me—was that the Coherence actually sounded better to my ears than the direct digital source in two key areas: a greater sense of envelopment by the music; and a greater solidity, or "body," to sonic images.

Perhaps these subtle improvements over the direct source were due to the reduction of high-frequency artifacts from the processor's output by the low-pass filtering and CMR qualities of the preamp's input transformers. While I'm speculating here, that's one plausible explanation. Your mileage may vary, depending on your source components and electrical environment. Nevertheless, the Coherence was the overall winner in these revealing bypass tests—one reason it's still my reference preamp.

But as illuminating as A/B tests are, they don't fully convey the musical impact of a given preamp in a given system. Only extensive listening to a wide variety of familiar material can do that. And it was over the long haul that the Coherence and Cadence really shone.

Enduring sonic characteristics of the Rowland rig included crystal-clear boundary definition of the soundstage combined with an uncannily seamless resolution of acoustic space within those borders. This gear conveyed such a high degree of transparency and transient dexterity that I could easily identify faint recording nuances and the finest imprints of source components. Delicate harmonic textures were vividly preserved during their journey through the preamp, and both the leading edges and decay tails of transients were cleanly delineated with seductive effortlessness, yet without suppressing the rhythmic drive of music or making it sound overly recessed. Indeed, the Coherence portrayed outstanding broadband dynamic contrast.

But perhaps most striking was a unique combination of two of the attributes mentioned above. When I listened to good recordings through the Coherence, I heard a deep, expansive soundscape anchored by superb low-frequency grip and extension, along with a powerful sense of being enveloped by both the music and the recording venue. In my experience of components that convey good depth, the soundstage usually starts a fair distance behind the speakers and extends back from there, lending the sound an overall laid-back perspective. Through the Coherence, the soundstage and instrumental images were spread across the breadth and depth of the room behind the speakers, while a subtle yet tangible sense of the venue's acoustic extended beyond the front of the speakers, embracing me with a powerful sensation of presence. Obviously, the speakers and the rest of the system must be up to the task, but this appealing amalgam of sonic illusions really stood out with the Coherence at the helm.

Wrap-up
Regardless of the actual cause-and-effect relationships that led to the stellar performance of the Coherence/Cadence, there's no denying that the system constitutes a tour de force of preamplifier design. However, though this combo's sound quality has not been surpassed or equaled in my living room, at least two other line-level models pending review have come close enough—and for considerably less than $17,800—that I can't make a blanket recommendation if sound quality is your only criterion.

I do, however, strongly endorse this dynamic duo to anyone who insists on the very best across the board, including a bulletproof interface to the outside world to ensure rock-solid stability regardless of your environment and associated gear; who expects robust reliability for long-term, trouble-free performance; who demands true reference-quality sound without the preamp adding a dominant signature of its own; and who places high value on superb workmanship, and an aesthetic design in which form and flexibility of function are beautifully and uniquely realized.

If this describes you, it's imperative to audition the Coherence before choosing a new preamp to anchor your reference system. Likewise, for analog devotees who wish to hear all of the wonders buried in your favorite wax, the Cadence belongs at the top of your wish list. Even if this system's hefty price puts it beyond your consideration, every audiophile should take a serious listen to the Coherence and Cadence, should the opportunity arise. You'll surely be enriched.

Company Info
Jeff Rowland Design Group
P.O. Box 7231
Colorado Springs, CO 80933
(719) 473-1181
Article Contents
Share | |
Site Map / Direct Links