Imaging through the SX-1000R was laterally precise to the point that on some cuts I could not only pinpoint each primary instrument accurately, but the secondary and tertiary players also occupied distinct locations across the soundfield. On the 192/24 MQA version of the Cars’ “Just What I Needed,” I could not only hear Elliot Easton’s muted rhythm guitar on the left, but also the secondary rhythm guitar that was nestled just to the right and behind Ric Ocasek’s lead vocals, in front of the drum kit in the center of the soundstage. Unlike most versions I’ve heard in which that center rhythm guitar track gets buried by the drums halfway through the cut, on this MQA version that guitar remained distinct throughout.
Soundstage width was determined more by each musical selection than by the system itself. On some cuts, such as Chance the Rapper’s “Same Drugs” via Tidal, the synth drum pans extended from one wall in my listening room all the way to the other. On Thin Lizzy’s “The Cowboy Song” from their Live and Dangerous album, the crowd’s sounds on the Tidal MQA version were even wider than the band’s. Switching to a mono source, Charlie Christian’s Genius of the Electric Guitar on CD, the entire band on “Flying Home” seemed no wider than a strand of spaghetti held by one end.
Treble extension was both smooth and incisive. There was no loss of air on the flute and piccolo on my own live concert recordings. Also, when I compared MP3 versions of several recordings I know well with full-res or hi-res versions, the MP3s lacked that last bit of air and treble extension when compared to the uncompressed versions played through the SX-1000R.
Bass extension, speed, and pitch definition through the SX-1000R proved to be among the best I’ve heard from any power amplifier. Take DJ Snake’s “Too Damn Low” from Tidal—the SX-1000R preserved the “puff of air” that accompanied the low-frequency attack. Also, the pitch of the synth drums was easy to identify and remained easy to hear throughout their decay from low to too damned low. I have my Spatial M3 Turbo S loudspeakers set up so their bass rolls off naturally without any crossover-imposed augmentation or restriction. Even when the pair of JL Audio Fathom f112 subwoofers were turned off, plenty of well-defined and well-controlled upper and midbass remained.
Inner detail and low-level information retention through the SX-1000R were exemplary. Listening to the remastered MQA version on Tidal of Joni Mitchell’s “Blue” all the subtle micro-dynamics of the slightly fluttery piano as well as the variations of her vocal vibrato were obvious. On the well-recorded “live” album Cayamo Sessions at Sea by Buddy Miller and Friends, on the “Angel from Montgomery” cut featuring Brandi Carlile and Lone Bellow, it was easy to hear every instrument, including the cello drone and the background fills.
When I compared the SX-1000R with the power amplifier I reviewed most recently, the Bel Canto REF600M ($2495 each), I noticed that the former had more precise lateral imaging, but the latter had a better sense of depth. Also, the SX-1000R’s images had better defined edges while the Bel Cantos’ had greater dimensionality but less distinct edges. There was some subtle difference in image height between the two amps with the SX-1000R having a consistently higher image (but not by much). In presentation the SX-1000R was a bit more forward, with the listening perspective moved two or three rows closer.
Another power amplifier on premises for comparison was the Pass X150.8 ($6400). The Pass projected a more three-dimensional image than the Wyred 4 Sound. Also, the overall presentation through the Pass seemed more relaxed, but with an equal amount of low-level information and detail. Like the REF600M, the X150.8 had a less forward presentation than the SX-1000R, but it also had a greater sense of intimacy, envelopment, and bloom. The X150.8 also created a slightly larger image overall, with greater height, width, and depth. Overall, the Pass X150.8 is one heck of a fine power amplifier.
I also have a Pass X150.3 power amplifier that I’ve used regularly over the past 25 years. Compared with the SX1000R the X150.3 was noticeably noisier at the speakers with a louder hiss level and a small amount of low-level buzz. The X150.3 had a warmer and less controlled midbass that lacked the definition and detail of the SX-1000R. The X150.3 was also less forward in its image presentation, more like the Bel Canto REF600M and Pass X150.8. Finally, the X150.3 was more three-dimensional than the SX-1000R, but the SX-1000R had more precise lateral imaging. As I switched back and forth between the two amps I kept thinking that the ideal power amplifier would possess a combination of the best characteristics of each—which would result in it sounding much like a Pass X150.8.
At the beginning of the review I posed the question of whether the latest switching amplifier technologies equaled the sonic performance of more traditional linear Class AB amplifiers. While I found that the SX-1000R performed at a very high level, it did not quite equal the current-production Pass X150.8. But it also costs $2800 less and will use substantially less energy during its lifetime. So, while the SX-1000R does not yet surpass a cost-no-object traditional-circuit topology, it is, without a doubt, a fine and near-state-of-the-art performer.
If you require a power amplifier that can generate oodles of effortless output, runs cool, produces a very precise lateral soundstage, has substantial bass extension and control, has a neutral harmonic balance, and is exceedingly quiet, the Wyred 4 Sound SX-1000R should be on your short list. It does its job with understated aplomb so you can focus on the music. Also, I have little doubt that, like its predecessor the SX-1000, the Wyred 4 Sound SX-1000R is practically a shoe-in for a seventh TAS Editors’ Choice award. It is simply that good.
Specs & Pricing
Type: Switching (Class D) monoblock power amplifier
Output power: 625W into 8 ohms, 1225W into 4 ohms
Inputs: Balanced XLR and unbalanced RCA
Output impedance: 0.005 ohms
Dimensions: 8.5" x 4.125" x 13.5"
Weight: 13 lbs.
Price: $1799 each
WYRED 4 SOUND
4235 Traffic Way
Atascadero, CA 93422