Soulution 330 Integrated Amplifier

Balancing Act

Equipment report
Integrated amplifiers
Soulution 330
Soulution 330 Integrated Amplifier

When you think of almost anything made in Switzerland, what comes to mind? Extreme precision, pristine aesthetics, painstaking research, and exemplary quality. (And yes, as you’d expect, this all comes at a considerable cost.) Enter Soulution. From its headquarters outside Zurich in Dulliken, Switzerland, the vaunted manufacturer produces some of the world’s finest solid-state audio components under the watchful eye of its founder and chief designer, Cyrill Hammer. As other TAS reviewers (JV for one) have noted, Soulution gear offers sonically sophisticated designs that involve a number of patented technologies.

Can such a celebrated manufacturer find a way of producing an outstanding product worthy of the company’s name yet priced considerably lower than its typical offerings? Trickling down sophisticated, proprietary technologies can be one solution (pun intended). Of course, the implications of the “trickle-down” theory of audio are vast and even controversial. How and where can you cut corners while still maintaining the sonic and user-experiential qualities that customers want and expect from your brand? Much like the sound in an audio system, the right balance must be struck.

The good news here is that with its 330 integrated amplifier (from the 3 series, which also includes the 311 stereo amp and 325 preamp), Soulution has succeeded in finding ways to offer a large number of its signature qualities—sonically, aesthetically, and functionally—at a fraction of the cost of its flagship 7 series and mid-tier 5 series components. That said, we’re not talking inexpensive here—this is the high end, after all. But the Swiss maker’s latest lineup does significantly reduce the price-point of entry for acquiring Soulution sound. And because the 330 is an integrated that packs so much in a single chassis, especially if you choose the DAC and/or phono board options, you get that much more bang for your (considerable) buck. Those who prefer separates will be interested to know that the 3 series is modular—that is, the 330 contains the preamp and stereo amp sections from the 325 and 311, respectively. I’d experienced the joys and super-powers of Soulution’s upper-end electronics at many an audio show and had also heard the Swiss maker’s 7 series gear upon occasion at JV’s house. So I was curious to discover what Soulution could offer by way of an integrated—a long-awaited entry within the company’s lowest-costing series. Spoiler: It was worth the wait.

The 330’s look and feel is classic Soulution: clean and non-fussy, understated and elegant. Solid yet streamlined, the brushed-aluminum chassis sports gently sloped edges, a dignified finish courtesy of in-house CNC machining. The red LED display shows what’s happening as the unit’s starting up or shutting down (e.g., STARTING, DIS-CHRG, etc.), as well as the volume level and the input in use. Apparently no corners were cut here. If a Soulution chassis were a garment, it might be a tuxedo: formal and uniform, but with just enough elegance and functionality to suit the occasion. It speaks to a serious, no-nonsense engineering approach, while also raising the bar for what could have been merely ordinary. I’d venture to say it reflects Soulution’s sonic properties, too: solidly three-dimensional with a sense of body, while eschewing clinical characteristics in the vein of, say, a hospital diagnostic machine.

The front panel bears the Soulution name and model number in lower-case text, with a large push-button knob to the right (it’s labeled “volume,” but does much more); to the left off-center are three small push-buttons: power, mute, and prog (to enter “program” mode), and a smallish, black display window that shows virtually all the amp’s goings-on via red LED text. The review sample I was sent contained the optional phono board but not the DAC. Included with the 330 are an IR-remote control, power cord, link cable, a laminated sheet with four graphs showing measurement results (a tube aficionado friend noted that the graph showing the 330’s THD+N vs. power measurements appear more akin to those of a tube amp than a solid-state one), and a smartly conceived and organized 24-page, spiral-bound user manual nearly as elegant as the unit.

As befits a classic integrated, the Soulution 330 comes standard with preamplifier and power amplifier sections; as noted, a phono board and/or DAC section are also available as separate options at additional cost ($3500 for the phono, $4800 for the DAC). The mc phonostage contains a wide range of user-adjustable impedance (loading) options—20 to 1260 ohms via a relay-switched resistor network. But unlike Soulution’s upper-tier phono preamps, the 330 does not offer adjustable gain. Phono gain is fixed at 60dB (though the linestage section can add another 10dB of gain by increasing the volume to levels between 81 and 90). For both left and right channels, the volume control utilizes relay-switched precision resistors; click-free adjustments are made possible through the use of a PGA-based parallel volume control path that’s only active when the volume is changed. (For more on gain and volume control, see the sidebar interview.) When equipped with the optional DAC board, which features the same Burr-Brown PCM1792 DAC chip used in the top-line 760, the 330 comes with network, USB, SPDIF, and AES/EBU inputs. (See sidebar interview for more on the DAC option.) 

At the core of the 330’s power-amp section, according to the user manual, is an innovative voltage-amplification stage that consists of a series of linearized amplifiers that function up to a cut-off frequency of 80kHz. The 330 outputs 120Wpc into 8 ohms (240Wpc into 4 ohms; 480Wpc into 2 ohms). That might not sound like a lot, but watts can be deceiving; the 330’s quality power goes a long way in both its drive capabilities across speaker loads and its superb sonics. A few of the outstanding attributes (among many) I’ve come to associate with Soulution components are an exceedingly low noise floor, plenty of air, and a noticeable continuity or sense of smoothness—an evenhanded ease when reproducing music. These qualities enhance realism by removing certain kinds of artifice. (A contributing factor behind these characteristics must be the quartet of switch-mode power supply modules with multi-stage filter networks that Soulution employs. In addition to being well-shielded from the amplifier boards, these switch-mode modules are also said to provide voltages that are more stable and lower in noise compared to other types of power supplies.)