There’s an old saying that more or less goes, “Never judge a book or an amp by its cover.” Exhibit One: the Creek Evolution 100A—outwardly an exemplar of modesty—the quintessential stealth integrated amplifier. With its engraved front panel and chunky control knobs it mirrors its slimline, mild-mannered sibling, the 50A, in most every detail. But beneath the conservative exterior skin of the Evolution 100A lurks a different beast, and underestimating its capabilities would be a serious mistake.
Power output is rated 110Wpc into 8 ohms, a big jump over the 55Wpc Class AB Evolution 50A. It owes this power boost largely to an all-new circuit design. However, shoehorned into the case is also a “super-size-me” power supply. The 360-watt, low-profile, toroidal mains transformer is outfitted with multiple windings for high and low voltages and currents to separately feed the power amp, preamp, and digital circuitry. In its literature, Creek credits its long-standing design policy of paralleling several small capacitors in the power supply to create an ultra-high-specification capacitor with low inductance and ultra-low impedance. This improves filtering and helps boost output from a relatively small amplifier.
Like the Evolution 50A, the 100A uses four Sanken Darlington transistors per channel with built-in thermal compensation. However, to increase the power output without expanding the chassis’ waistline, Creek Audio engineers developed a Class G circuit—a dual-rail design that mostly runs at a lower voltage for power levels up to 25 watts, but that, upon demand, can automatically swing to a higher secondary voltage to increase the output power capability to over 100 watts into 8 ohms.
Dominating the front panel is a large, white-on-black OLED display that’s sharp and readable at realistic distances. Its brightness is adjustable. Flanking the display are the same backlit soft-push buttons found on the Evolution 50 Series, which offer a firm, yet tactile feel. Augmenting the volume knob are balance and tone controls, which in my experience always come in handy. The Evolution 100A is available with either a black or silver brushed-aluminum front panel, and is equipped with two sets of loudspeaker binding posts, with local and remote switching for A and B outputs.
The preamp section provides high levels of flexibility through five unbalanced and a single set of balanced inputs. It’s thoroughly configurable via modular options that slide into back panel “smart slots.” Principal among them is the Ruby DAC/Bluetooth/FM module that replaces Input 5 and features a pair of 24-bit/192kHz SPDIF inputs, twin optical inputs, and a 24-bit/96kHz USB input, as well as Bluetooth and FM reception. If you’re looking only for a dedicated tuner add-on, there’s the optional Ambit plug-in tuner module, which essentially turns the Evolution 100A into a traditional receiver. When fitted, all the tuner’s functions are imported into the display and controlled by the left-hand buttons and control knobs, and remote control. Another modular option is the Sequel 2 phonostage, which replaces Input 1 and plugs into a dedicated connector on the preamp PCB. It’s supplied in three versions (40dB moving-magnet, 48dB moving-coil, and 54dB moving-coil).
The Evolution offers a dedicated headphone circuit. In this case “dedicated” means that rather than generate headphone output off the power amplifier, the output is derived from a separate amplifier located on the preamplifier circuit board. And this is no throwaway, either—it’s a solid, satisfying performer capable of driving low-impedance portable-player earbuds as well as higher-impedance over-the-ear designs. For those seeking sheer convenience, the Bluetooth setup was as easy as screwing in the included antennae and enabling the “Evolution BT” on my MacBook via My Settings/Bluetooth/My Devices. Quasi-computer-phobe that I am, it’s always “fingers crossed.” But BT worked like a charm—that is, to the extent it can. Actually, it performed like all BT devices in my home—less than pristinely focused and somewhat compressed. Great for parties, but IMHO leave the serious listening to Ruby.
During my evaluations, the Evolution 100A was given an Olympic-level workout driving top-notch loudspeakers such as the Wilson Sabrina, the Spendor S7, and the Vandersteen Quattro Treo CT. And while I fully realize that most Creek owners are not going to put this amp through the withering gauntlet of such high-resolution loudspeaker pairings that doesn’t mean it wasn’t game for the challenge. In each scenario, the Evolution 100A was rock-solid and stable across the frequency spectrum, with full-bodied bass, a warm, slightly chesty midrange, and relatively smooth and forgiving treble throughout Appalachian Journey [Sony]. It’s a straight shooter in that it didn’t shine headlights on any particular octave range, and it’s not an additive sound in the sense of being tipped-up or rolled-off at the extremes.