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Soulution 330 Integrated Amplifier

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.)


The 330 in Action
To get the 330 integrated up and running, basic setup is straightforward; default settings on the very low side are in place for volume, phono impedance, etc. As with Soulution’s other celebrated products, the 330 is no slouch when it comes to a comprehensive, even mind-boggling array of features and functions that ought to satisfy even the tweakiest of audiophiles. But these are options on offer, so you only need dial in those that please you—or that your system may require. Since the menu is so extensive (and I have a word count to adhere to), I’ll highlight just a few items. 

The front-panel push-button control knob’s capabilities far exceed its humble “volume” designation. Sure, controlling level is its primary job, but think of a butler who’s also a chauffeur, a cook, an event planner, and a mechanic, and you’ll get the idea. More akin to a master controller, its other duties include (but are not limited to) input selection—hold the button down for a moment until three LEDs light up and you can scroll through the input options (1 through 4 plus phono), then push the knob again to select the desired input. A press of the “prog” button initiates “program mode,” where turning the knob allows scrolling through myriad program functions. To select one, push the knob again. Once within a given program function, you can scroll through its values and make a selection by, guess what, pushing the knob. To exit, simply press the “prog” button again. The hierarchy is logical and pretty easy to master once you get the hang of it. Program function selections include defining values for start-up defaults (volume, inputs, etc.), multi-amp and/or surround setups, display brightness, remote control ID, phono options, polarity, firmware (which can be updated via the 330’s Link-Com USB input), among others. Apart from switching between inputs (obviously) and assigning a couple of volume defaults, I mostly just made adjustments to impedance within the phono section, trying out different values for the two turntables and cartridges deployed during my audition. Another noteworthy feature is the RIAA-IEC high-pass filter you can activiate “on the fly” during playback.

A confession: I used the remote control far less than I expected. It’s commendable for its extraordinarily sophisticated in-depth capabilities and its ability to let you access virtually all control functions from your listening seat, but I never quite got used to its buttons’ first-order functions. It certainly worked well and had a logical system (clearly explained in the user manual) and path to menus, settings programming, and so on, but personally I didn’t find it to be especially intuitive beyond the basics. More importantly, I genuinely did enjoy that main front-panel push-button control knob’s immediacy, ergonomic feel, subtle clicks, and the versatility of functions that could be accessed from a single point of direct contact. Also this way I never needed to concern myself with a direct “sight line” from remote to amp.

Because my review sample came equipped with the phono-board option, I explored that first and foremost (primarily with Clearaudio’s Performance DC Wood turntable, Tracer tonearm, and Stradivari V2 cartridge, but also with Acoustic Signature’s Double X turntable, TA-2000 tonearm, and Air Tight PC-7 mc cartridge). As noted the review sample did not include the DAC option, so my other listening was digital streaming (mostly Tidal via Roon on my MacBook Air) and CDs via an MBL Noble Line N31 CD player/DAC. 

When I first fired up the Soulution 330 for several days of ongoing break-in (before I started critical listening), I noticed the output volume seemed quite low and the default volume setting was only 10 within a range of up to 90. At first I hesitated to increase SPLs, but crank it up I did, finding levels between 50 and 70 suitable for most source material. I was also a bit nervous about how the MBL speakers, which are designed to pair with MBL’s own electronics, such as the N51 integrated, would take to the Soulution integrated’s power. They fared beautifully—the Soulution’s signature dimensionality, detail, and smooth, continuous power with grip and headroom to spare complemented the Radialstrahlers’ unique omnidirectional dispersion, substance, and spaciousness. I’m speaking primarily of LP listening here, but I don’t believe I’ve ever heard Red Book CDs sound as thrilling in my home as they did through this setup—and not only those of great recordings. I’d recently picked up an original 2-LP pressing of Tuscon-based Calexico’s Feast of Wire [Quarterstick QS 78] and for fun I pulled out the Canadian-made CD on the same label. Turns out the disc was impossible to play as mere background music. The vinyl version was swell too, but this was the CD. Its off-kilter desert-noir charms—fully rendered Tex-Mex accordion bellows; the sharp, brassy blasts of mariachi horns; crisp, clean guitar picking; and Joey Burns’ natural, often-understated vocals—kept tearing my attention away from my computer work at my faraway desk by evoking sonic scenes of tumbleweeds and border towns. As with LP playback, backgrounds were as astonishingly dark and quiet as a moonless desert night.

For vinyl listening through the 330, I experimented with increasing and decreasing the phono impedance—the default setting is 100 ohms—with varying results (much depended on the recording, too, of course). Generally, I preferred lower impedances; higher values seemed to bring more sonic weight and density but also skewed slightly less lively and realistic due to a reduced sense of air and overall openness. Staging also felt a bit more closed in at times. However, such gradations were relatively subtle unless more drastic adjustments were applied. For the 0.6mV mc cartridges in use I settled on values of from 200 (240 most often) to 400 ohms, tending to prefer higher values for rock ’n’ roll and other harder-hitting material. Lackluster recordings were rendered pretty faithfully without much added sweetening, yet still seemed to be sonically spit-shined, rendered with body and energy. The 330 is not dead neutral and if you’re seeking X-ray transparency this might not be the ideal amp for you. That said, it brings plenty of solidity and power-range oomph, preventing music from sounding thin or threadbare but more textural, dimensional, and substantial. 

Singers’ voices displayed a certain purity and realism, which meant that tiny details and nuances in performances stood out more. A listen to “Don’t Wait Too Long” on Mobile Fidelity’s delightful LP reissue of Madeleine Peyroux’s Careless Love highlighted her subtle, sassy vibrato stylings that can be easy to miss on less resolved systems, alongside peppy Hammond B3 accents and silky-smooth snare and cymbal brushstrokes—so fine, so delicate, so real. On “Dance Me to the End of Love” pitch accuracy on vocals, upright bass, and piano, a notoriously challenging instrument to reproduce, also seemed spot-on, as did the musicians’ placement. All made for a beautiful, well-balanced, airy, and oh-so-natural presentation. 


In addition to voices, violin also tended to sound incredibly realistic with the rendering of micro-dynamics allowing subtle characteristics to be revealed. On Diabolus in Musica: Accardo interpreta Paganini [Deutsche Grammophon], Salvatore Accardo’s virtuosity was on full, fiery display: natural instrumental harmonics, attacks, body, and textures emerged from a quiet backdrop as he tore through flights up and down octaves. In “La Campanella” the tiny tinkling chime in the right channel registered clearly, convincingly placed farther upstage. A palpable sense of the orchestral choirs’ presence, scale, and positions came through as well. And I liked the virtual impression of where I was “sitting in the hall,” several rows from the stage, not too close, not too far away.

The Soulution also reproduces bass to satisfying levels, here pushing the MBLs to reach for those deeper octaves—be they doublebass or Fender bass, electronic dance music, or even organ. No, the MBLs didn’t plumb the deepest depths or rumble my room (maybe I need to bring back some subs, ha!) but I generally didn’t feel I was missing out. Some electronics perform better with, say, classical music than with hard rock. As described, the Soulution impressed with whatever genre or medium I threw at it. 

Among the 330’s greatest strengths were how it (somehow) seemed to convey musicians’ and singers’ individual styles and performances realisically with a high degree of detail and nuance—and it did so with greater consistency than I’d ever experienced in my listening room. On The National’s Sleep Well Beast LP [4AD], at the very end of the title track my ears picked up on what sounded like horns running rapid-fire through rehearsal scales; I hadn’t heard that before. “Carin at the Liquor Store” seemed to carry more weight of expression—even sounding closer to live—than I’d experienced in its playback on other systems. Higher resolution and textural details revealed compelling insight into the sad, slow waltz’s finer points, from Matt Berninger’s slightly raspy, throaty baritone to Aaron Dessner’s somewhat subdued yet deftly searing Fender guitar solo, which cuts through the bittersweet moodiness of Bryce Dessner’s slow-burn, slow-build piano chords. 

High-end audio is so often about compromises, trading one quality for another. What sets the Soulution 330 integrated apart is its ability to strike just the right balance of musical and technical elements within a winning feature set, and to manage to deliver the sonic goods beautifully across so many recordings and styles. Moreover, the company has succeeded in keeping so many of its best sonic characteristics while paring down parts and pricing. The integrated gets out of the way of the music in the right ways but delivers the right stuff. This exquisite Swiss integrated might still cost a pretty penny but if you have the coin, I’d highly recommend auditioning it. For those yearning for Soulution’s Swiss sound and tech built-to-last, with the 3 series there’s never been a better time to invest in some of the finest solid-state around.

Specs & Pricing

Type: Integrated amplifier (phono board and/or DAC optional)
Power output: 120Wpc into 8 ohms, 240Wpc into 4 ohms, 480Wpc into 2 ohms (dynamic)
Analog inputs: 2x XLR, 2x RCA, 1x phono mc (optional) 
Digital inputs (DAC option): USB-B, SPDIF, AES/EBU, Network/LAN 
Outputs: 2 pairs of loudspeaker binding posts
Phono (optional): Impedance, 20–1260 ohms; gain, 60dB
DAC (optional): SPDIF impedance, 75 ohms; AES/EBU impedance, 110 ohms
Frequency response: DC–800kHz
TDH+N: <0.001%
SNR: >120dB
Dimensions: 430mm x 142mm x 490mm
Weight: Approx. 30kg/66 lbs.
Price: $22,500; add’l. options include phono board, $3500; DAC, $4800

Spemot AG
Industriestrasse 70
CH-4657 Dulliken

AXISS AUDIO (U.S. Distributor)
17800 South Main St. Suite 109
Gardena, CA 90248
(310) 329-0187

ASSOCIATED EQUIPMENT (system for this review)
Loudspeakers: MBL Corona Line 126 Radialstrahler omnidirectional speakers
Analog sources: Acoustic Signature’s Double X turntable, TA-2000 tonearm with Air Tight PC-7 mc cartridge, and Tango Reference phono preamp; Clearaudio’s Performance DC Wood turntable, Tracer tonearm with Stradivari V2 cartridge, and Balance V2 phonostage
Digital sources: MBL N31 DAC/CD Player, MacBook Air running Tidal via Roon 
Amplifiers: MBL N51 integrated amplifier; Soulution 330 integrated amplifier with phono board
Power conditioners: AudioQuest Niagara 1000 conditioner; Ansuz Acoustics DTC box
Cables: AudioQuest power cord; Ansuz Acoustics DTC and D2 cables and interconnects
Accessories: Stein Music H2 Harmonizer boxes
Room treatments: Zanden Audio
Equipment racks: Critical Mass Systems Maxxum

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