Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click this link.

Sound Performance Lab (SPL) is based in Niederkrüchten, in North Rhine-Westphalia, Germany, and has manufactured professional and home audio gear since 1983. With a deep background in studio mastering, SPL founder and chief designer Wolfgang Neumann got the idea of starting his own company while managing a recording studio in rural Germany in the late 1970s. In those days, the US dollar was valued at roughly 3.5 times the deutschmark, and importing US-made studio gear wasn’t cheap. This led Neumann to begin the tinkering that ultimately convinced him he could design and build better-sounding products and sell them at prices significantly below those of imported US equivalents. By 1983, he’d begun selling his products under the SPL brand, but struggled with distribution until, in 1985, he met Hermann Gier.

At the time, Gier, who is now CEO of SPL, was taking bass-guitar lessons from a fellow who was endorsing a brand of speakers marketed by SPL’s distributor. Intrigued by Neumann’s ability to conceptualize from scratch and bring to market outstanding electronic components, Gier asked him to build him a bass preamplifier. And so began their partnership.


SPL currently offers myriad models in their Mastering, Studio, Plugin, and Professional Fidelity lines, the last comprising nine models for high-end home audio: two analog preamplifiers, one with and one without a DAC; two headphone amplifiers; one preamp-headphone amp; one phono stage; a standalone crossover; a stereo power amplifier; and the subject of this review, the Performer m1000 monoblock amplifier. A standalone DAC is in the works.

Good things come in small packages

The Performer m1000 is a solid-state, class-AB, monoblock power amplifier ($8598/pair, all prices USD)—a charmingly svelte little powerhouse measuring 11ʺW x 8ʺH x 14.75ʺD. These dimensions are the only thing diminutive about this amplifier, though; it weighs 54.7 pounds and is specified to punch out 1000W into 2 ohms, 750W into 4 ohms, or 420W into 8 ohms. SPL claims that the m1000 is quiet, with specs of 123dB signal/noise (A-weighted), 26dB of gain, and a damping factor of >280 (1kHz at 8 ohms). With such specs claimed for so small an amp, I had to peek under its hood to confirm that it’s not some funky class-D hybrid. When I did, I realized two things: The Performer m1000 is densely packed with high-quality components, and there’s nothing class-D about it.

The Performer m1000’s steel chassis is built on two levels. Two big heatsinks occupy the entire left and right thirds of the upper story. Between them is a circuit board containing, from back to front, a 120V DC input amplifier, a speaker on/off relay, an HF (>300Hz-300kHz) filter coil output, temperature sensors for the cooling fans, and a DC protection circuit. Viewed from the top, each of 12 bipolar power transistors can be seen to be mounted directly to the heatsinks. The m1000’s ground floor itself contains two layers of printed circuits, the lower bunk dedicated to 66 capacitors, each with 1000µF of energy storage; the upper bunk comprises the standby power supply, the inrush-current-limiting relay and limiting resistors, and 34 more 1000µF caps, for a total of 100,000µF of energy storage.


Each side panel of the m1000 is occupied by three cooling fans that begin to spin when the amp’s internal temperature hits 131°F (55°C), and spin faster as the temperature rises. The total noise of all six fans working at maximum speed is a claimed 19dB, ensuring near-silent operation. The front half of the lower section is occupied by a beefy 1375VA toroidal (donut-shaped) transformer secured to the chassis with eight damped screws, to reduce the transfer of vibrations from transformer to chassis. Directly in front of the transformer, in what seems an impossibly small space, is a 50A bridge rectifier. At idle, each m1000 drains about 50W from your power supply to keep everything fully energized—when put in standby mode its energy consumption falls to just 0.3W.

That 120V DC input amplifier I mentioned is important. Every Professional Fidelity model includes SPL’s unique VOLTAiR technology, aka 120V DC Audio Rail. This works by enabling each component to operate at the full rail voltage of 120V supplied by the mains socket. In most audio components, AC power is accepted from the wall by the transformer and converted to a secondary DC voltage of, typically, +/-15V or less—anything more would cook the component’s receiving operational amplifier (op-amp). SPL has developed their own op-amp, the SUPRA, capable of handling ±60V or 120V DC. They say the advantages of this are increased dynamic range and headroom with lower levels of total harmonic distortion and noise (THD+N): in the case of the m1000, 0.008% at 1kHz at 1000W into 2 ohms.


I replaced the m1000’s stamped-steel cover to enjoy its minimalist design. The brushed-aluminum faceplate can be ordered in black, silver, or red, and each amp can be further customized with the insertion, in a shallow central depression, of a magnetically attached, smartphone-sized, decorative nameplate (also in black, silver, or red). Toward the bottom of this depression are three indicator LEDs: from left to right, Protect, Power, and Temp. Directly below these is the VOLTAiR logo, flanked on left and right by, respectively, “Performer m1000” and “Mono Power Amplifier.” The single piece of bent steel comprising the top and side panels is mostly air—vents that serve the heatsinks and fans.

The rear panel is logically laid out. From top to bottom are: a trim adjustment knob just right of center, for adjusting the input sensitivity in increments of 0.5dB, to fine-tune the amp when a pair of them is used to biamp one speaker. To the right of this is a single balanced (XLR) Slave Thru input for biamping, and another for the main input. Directly below these is a pair of five-way binding posts and a reminder that the amp’s minimum load is 2 ohms. Below those is a 12V trigger input. To the left of the binding posts are an IEC power input, power rocker, and current inrush fuse. The Performer m1000 sits on five high-quality feet of damped aluminum.


The Performer m1000 is warranted for five years.


Replacing my Classé Delta Mono amps with the m1000s was a snap. Kimber Kable Select 6063 speaker cables tethered the Performer m1000s to my Paradigm Persona 7F loudspeakers, and Kimber KS 1116 analog interconnects linked the SPLs to my Audio Research Reference 6SE preamplifier and PS Audio DirectStream DAC (with Bridge II network soundcard), the latter fed by an Intel NUC computer running Windows 10 and Roon. Analysis Plus provided all digital links, and all electronics were plugged into a Torus AVR 20 power conditioner with Clarus Crimson power cords.

Smooth operator

As soon as I began my serious listening, the SPL Performer m1000s reminded me never to judge a book by its cover. “Sirius,” the instrumental introduction to the Alan Parsons Project’s Eye in the Sky (24-bit/192kHz FLAC, Arista), filled my room with punchy kick drum, arresting guitar, and a wonderfully rich yet clearly layered soundstage anchored by, front and center, the voice of Eric Woolfson. The slightly warm yet powerful sound of the m1000s helped bring a sense of balance to this and every track on this album—things I rarely hear from a solid-state class-AB amp. About the best way to describe the Performer m1000’s sound is “tube-like.”


Ferruccio Spinetti’s double-bass notes in “Fever,” from Musica Nuda’s Live à Fip (16/44.1 FLAC, BHM), were resolute, articulate, and tuneful, but lacked the punch and drive I’ve come to relish from my Classé Delta Monos. That’s not to dis the m1000s—they just can’t quite compete with amps more than twice their price and weight. As I listened deeper into “Fever,” I noticed that spatial cues—e.g., the air around Petra Magoni’s voice, and an apparently vast space filled by audience applause—were marginally diminished in favor of harmonic fluidity and a beguiling sense of ease. The m1000s didn’t sound dark or too warm, nor did they shine a spotlight on the music, in the way of such resolution-focused amps as my old Simaudio Moon W-7Ms. And their dynamic drive and transient control commanded my respect. Magoni’s singing gripped my attention often in this track, and I could easily appreciate the SPLs’ control of the double-bass transients, which helped convey Spinetti’s enthusiastic playing.

I heard much the same while listening to “Trouble’s What You’re In,” from Fink’s Distance and Time (16/44.1 FLAC, Ninja Tune). String nuances weren’t thrust in my face but were hardly absent. Fink’s picked and strummed acoustic guitar sounded convincing enough in bite and tone for me to get an idea of the tension with which each string was tuned, and his voice lit up the stage with enough texture and breath to let me feel I was hearing him in concert in person. Another way to describe the sound of the SPLs is “convincing but not obvious”—the m1000s didn’t nitpick nuances, but instead communicated music fluidly while letting me choose which aspects of it I wanted to focus on. Some might call this sort of sound “musical”; I call it inviting.

With “Strangers,” from Halsey’s Hopeless Fountain Kingdom (16/44.1 FLAC, Astralwerks), the m1000s tamed the slightly overlit top end and let Halsey’s raspy singing rip. As surprised as I was by how punchily the SPLs reproduced this track’s synth bass, I was even more elated by the refinement the m1000s brought to an otherwise unrefined recording despite my getting quite spirited with the volume knob. They commendably delineated the differences in tone and texture between Halsey’s and Lauren Jauregui’s voices, and the soundstage on which both voices were imaged was expansive and immersive. Supporting synth and electric-guitar notes filled the breadth of the soundstage much as they do through my Classé Delta Monos.


Which led me to cue up “Perfect Sense, Part I,” from Roger Waters’s Amused to Death (16/44.1 FLAC, Columbia)—one of my go-to tracks when I want to evaluate how an audio component communicates spatial cues. In this track, especially its first 30 seconds, aural images sound as if they’re coming from everywhere in the room except the speakers. The m1000s left nothing to be desired, conjuring up Waters’s eerily Darth Vader-like voice about 3ʹ in front of the left speaker as he recants a backward spoken message. Taps of Graham Broad’s bongos were subtly locked at center stage, remaining present enough not to get lost behind the image of Patrick Leonard’s fluid keyboards about 3ʹ in front of my right speaker. When, at 1:50 into the track, Waters begins to speak, the image of his voice was large and chiseled dead center on the soundstage, replete with enough detail for me to hear the saliva in his mouth. I enjoy how this track envelops me in music and sounds, and the m1000s didn’t skip a beat in re-creating this effect.


All I had on hand to compare with the SPL Performer m1000s were my reference power amps, Classé’s Delta Monos ($22,000/pair). After lining up the SPLs and Classés side by side on the floor to ease cable swaps, I cued up some music and immediately noticed a discrepancy in gain confirmed by the two models’ specs: the Classés provide 29dB of overall gain, the SPLs 26dB. This difference negated the use of the m1000’s trim control, which I was forced to leave level at “0,” then manually adjust the output using my preamp’s volume control.

I kicked off my comparisons with the Alan Parsons Project’s Eye in the Sky. The most audible difference between the SPLs and Classés was in overall tonality: The Performer m1000s sounded a couple degrees warmer and a shade darker. The m1000s didn’t sound quite as liquid-smooth as the Delta Monos, and lacked a hint of bottom-end punch. But if only in terms of price, I wasn’t exactly comparing apples with apples.


Overall, I found the Performer m1000s enjoyable to listen to, and never got the impression that I was missing anything or that they fell short in any way—until I stacked them up against the Classé juggernauts. That’s saying a lot. Moreover, when listening to Halsey’s “Strangers,” I preferred the SPLs’ overall tonal balance—I could enjoy music at high volumes longer without having to worry about listening fatigue. I also appreciated how the SPLs mitigated the glare that commonly plagues this pop recording, thus letting me better enjoy the music.

Summing up

My two months of listening to SPL’s Performer m1000 monoblocks has left me impressed and a bit smitten with them. The m1000 packs one hell of a punch, in sound and in value. Not once did I feel it had to strain to produce enough output power, or that its sound was constrained in any way, even at very high playback levels. Furthermore, the Performer m1000s ran cool, look cool, and, if you’re brave enough to lift one, feel solid as a rock. But most important, the m1000s were compelling to listen to.


Add all of that together and the math is simple: Sound Performance Lab’s Performer m1000 presents a heck of a value proposition for anyone in the market for a high-powered, solid-state, class-AB power amplifier. Highly recommended!

. . . Aron Garrecht

Note: for the full suite of measurements from the SoundStage! Audio-Electronics Lab, click this link.

Associated Equipment

  • Speakers: Paradigm Persona 7F
  • Subwoofers: JL Audio Fathom f112 (2)
  • Amplifiers: Classé Delta Monos (2), Parasound Halo A 51 (multichannel)
  • Preamplifiers: Anthem AVM 60, Audio Research Reference 6SE
  • Digital-to-analog converter: PS Audio DirectStream with Bridge II network soundcard
  • Sources: Oppo Digital BDP-103 universal BD player; Intel NUC computer running Windows 10, Roon
  • Interconnects: Analysis Plus (digital), Kimber Kable Select KS-1116 (analog)
  • Speaker cables: Kimber Kable KS-6063
  • Power cords: Clarus Crimson
  • Power conditioner: Torus AVR 20

SPL Performer m1000 Monoblock Amplifiers
Price: $8598/pair USD.
Warranty: Five years parts and labor.

SPL electronics GmbH
PO Box 1227
41372 Niederkrüchten
Phone: +49 (0)2163-9834-0
Fax: +49 (0)2163-9834-20