SBS Designs S5 Series stereo amplifier

I’ve been living happily with the SBS Designs S2-Pro class AB power amplifier for the past year or so. It’s a terrific amp – dynamic, transparent, and quite revealing. When Clement offered the opportunity to listen to the new SBS Designs S5 Series power amplifier, I welcomed that opportunity. SBS, established in 2011, offers products created, designed & built by NYC-based Craig ‘Shorty’ Bernabeu and the former head engineer of Summit Audio, who is engineering SBS Designs. Bernabeu is a recording engineer, designing pro audio and custom high-end analog systems for use from studio to stage, and the “SBS” in the brand’s name (Systems By Shorty). The SBS Designs S Series amplifiers are offered as a traditional power amp line with massive power supplies and storage capacity and pure class AB output, delivering 300 watts @8 ohms per channel, 600 watts @4 ohms per channel, and a stable 1100 watts @2 ohms per channel. It offers a Slew Rate of 80 v/us (how quickly an amplifier responds to rapid input level changes), a THD of .03%, Damping of 400, a Frequency Response of 10Hz to 75kHz, and an Input Sensitivity of 1.4.

The SBS S5 Series amp measures 5.25″ tall by 17.25″ (including the front track mount handles and rear knobs) and has the standard rack mount front place that’s 19″ in width. It weighs 55 lbs. and takes up 3RU’s of rack space. The manufacturer includes a 10 yr parts and labor warranty. The S5 review sample has slotted intake vents and two chromed rack-mount handles, and its chassis is all black. A look at the rear of the unit shows an IEC power cable input, two balanced inputs, gain knobs for each channel, four banana speaker cable inputs, and a rear-mounted fan and second vent. The S5 Series sports the same chunky red power right and on/off power toggle switch (like on a guitar amp) as on the S2-Pro. I like that, simplicity.

Shorty Weighs In

To paraphrase a forum post by SBS Designs, “The SBS Designs HIFI amplifiers are voiced to sound amazing, they are extremely fast, very dynamic with very wide frequency response, for a very open and musical sound. They are rated conservatively with true continuous specs.” Shorty continues “The S5 High Current amp will output about 85V peak per channel, at 4 Ohms per channel and 1 kHz, and it will output about 75V peak continuously into a purely resistive load. The S5 has ten pairs of output devices per channel with dual 22,000 uF filter caps, one per rail, with a 1000 VA Transformer. “The S5 amplifier is a VERY HAPPY camper at 2 Ohm loads all day, all night all day. I run these on mid-bass and subs in clubs with zero cooling or audible issues at two ohms. The S5 will work with no problem or difficulty with passive networks that generally drive most amps crazy.

“In the near future, Annabella Audio (currently our handmade speaker brand) will become our high-end home audio brand, with a full line of amplifiers Analog X-Overs and a preamp, with the S Series, renamed the A-Series and upgraded, being the base platform we’ll build future designs from. The S2 will be renamed the A2, and we’re looking into a few changes to that product. The S5, renamed the A5, will be convection cooled and will include many upgrades. Both amplifiers and components will share wooden panels, complete with cosmetic changes.” On a side note, Keith Munson (assistant manager East-West Studios) used the S2 on near fields at East-West and wrote Shorty the following: “I was really impressed with the way it [the S2] sounded hooked up to some [ProAcs as] compared to the Bryson 4b.”

The SBS Designs S5 Series Amp’s Little Brother, The S2-Pro

My year with the SBS S2-Pro (reviewed here), revealed it as a nimble, dependable, and good-sounding companion. I quickly shifted to balanced cables throughout my rig, from phono stage preamp/DAC and over to SBS S2-Pro amplifier, which now resides on a short rack between the Double Impacts, connected 19 feet of cabling to my rig with a long pair of silver XLR cables. The S2 presents both depth and dynamics with nuance and snap, renders taut imaging, and offers an expansive soundstage on which engaging musicians and vocalists are quite fleshed out and real. The S5 Series power amplifier does this and more, with a meatiness and low-frequency delivery that’s just stunning… similar to that of the S2, with more power, capacity, and headroom.

When I told ST writer and brother-in-law, Tim Barrall, he remarked that my neighbors might indeed offer commentary on the amped-up bass performance. He may be right (so far, so good). Needless to say, these developments stunned me. But, let me be clear, it’s not that the bass is much fuller, rather the body of all instrumentation is more well-rounded. It’s not over-scaled; it’s just delivering a better, more fleshed-out performance with a greater sense of body. In that way, it’s quite stunning. More power, more finesse, more to love.

Listening

As I connected my Dynamique Audio Tempest 2 power and speaker cables to the S5 amp, I saw that each pair of banana jack inputs had been moved to each side of the rear face of the S5’s rear chassis (thanks, Shorty!). The S2 has the two pairs spaced quite close together, right next to a massive heat sink, making the connection of bulkier speaker cables a challenge. With that step complete, I plugged the amp into the Core Power Technologies EQUI=CORE 300, turned on the preamp, and waited for a beat or two before flipping the S5’s front-mounted chunky toggle switch to the up position. The fan spun up and promptly backed down to a very low level for uninterrupted listening. I was ready to go.

“Who Wears The Watch” from Sitka Sun’s sophomore release “All The Way West” (The Long Road Society 2021), available on bandcamp.com and streamed here using Tidal, there’s just more there to love. Imaging is tight, and the instruments are delivered with nuance and punch. On “Dauntless,” the drums and bass are holding court near center-right, with percussive fills quite far to the rear of a deep stage and horns fleshing out the center stage – each instrument has great body and more verve and pulls you in for a closer listen.

Susanna Aleksandra’s “The Siren” (Eclipse Music / Supersounds Music Oy 2021) was a recent and surprising discovery as I plunged deep into Tidal’s offerings. I was mildly intrigued by this singers’ voice and presentation, but it was her skating that captured my attention. As this first track progressed, there was clearly more for me to enjoy. Ms. Aleksandra skillfully creates songs with a mix of pop and jazz, and the backing band is relaxed and ready to pump out some great accompaniment. Once the third track, “Clumsy.” is reached, the gloves come off as everyone swings. Fantastic stuff!

The SBS S5 Series power amp dug in deep for Trio Grande’s self-titled effort “Trio Grande” (Whirlwind Recordings 2020) as it delivered dynamic excitement at the first jump. On Northbound, the album’s first track, Will Vinson, Gilad Hekselman, and Antonio Sanchez, cooked up a lively brew of sonic fun for these ears. The bass was strong, as though I have a sub (I don’t), the dynamics flowed freely and rhythmically through Elli Yeled Tov, as each musician stretched out and provided lines to the festivities. The stage is small, but the drum dynamics are close-miked and surprisingly punchy throughout this PRAT-filled feast. On Oberkampf, the band slowed pace as it rendered a rhythmic soundscape with a great growling guitar tone. The SBS S5 rendered this slow foray, swaying to and fro with great aplomb. The S5 Series amp didn’t miss a beat while providing plenty of full-bodied interest.

The trio plays a somewhat low volume fusion homage to John Scofield on “Scoville,” the guitar’s character is hard to miss, as is the arrangement… it’s so Sco-inspired! I love how this album is somewhat low listening level, not an ear-splitting effort. It’s low-level throaty and gutsy, with plenty of guitar-loving fun. Have I mentioned “fun” three times already? Well, there you go.

The S5 Series amp provided a far more meaty product. Everything has so much more body and weight. There’s an openness, dynamism, realism, and musicality that the S5 Series amp provides. A play of the Stefan Aeby Trio’s “llages” from their 2010 release “Are You…?” (Unit Records) showed how the S5 amp adds a more realistic body to instruments – the drums are so much more fleshy and realistic that I kept inching the volume up to enjoy the sensation of real drums – fast and agile transients enhanced the effect.

How Does the SBS S5 Series Compare to the SBS S2-Pro?

This is what I was reluctant to find out. After all, I didn’t want to see my SBS S2-Pro bettered and wish for more (we’re all somewhat protective of our choices, aren’t we?). I’ve lived with the S5 Series amp now for a couple of weeks without switching the S2 back in, so sonic memory had faded a touch. I took a deep breath, and, turning the volume down, I flicked the S5’s toggle to the off position, to which the S5 amp responded with its characteristic “thump.” I moved my SBS S2-Pro into place, reconnecting input, speaker, and power cables; after ensuring everything was successfully connected, I flicked the S2-Pro’s toggle on and played the same song. Regarding that thump heard as I powered the S5 Series amp down, as I paraphrase Shorty’s response here: “The thump is the caps dissipating energy. [This} will not harm any loudspeakers. In fact, you can drive this amp to complete saturation and will never send a square wave and destroy any loudspeakers… it would just sound distorted.”

I heard a nicely grounded and amply-bodied piano, weighty bass, and, when the drums came in, broad and bold dynamics with transients awash in speed and shimmer. There is an SBS Designs “house sound” that the two amps share! The S5 delivers more bottom, firmer body end a weightiness to instruments, but both amplifiers share transparency, dynamics, and musical truth. The S5 Series amplifier does push the boundaries farther into realism.

The less powerful SBS S2-Pro amplifier yields a smaller delivery of wattage to the 98.82 dB efficient Tekton DI’s (125 watts into 8 ohms and 225 into 4 ohms), compared to the S5 Series amp’s (over) double power output. The S2 Pro has a Slew Rate 100 v/us, a Sensitivity of 1.25 (S5’s is 1.4), clocking in with a THD of .02% (S5’s is .03%) – all quite similar to that of the S5 Series amp. Only the Damping Factor (100 to the S5’s 400), Frequency Response (the S2 reaches 100 KHZ), and power output differ, measurement-wise.

Final Thoughts

I thoroughly enjoyed my time with the SBS S5 Series power amplifier – it provided a robust air and added gravity, weight, and depth to recordings – and was happy to find it shares the character of its much appreciated little brother, the SBS S2-Pro – both pure class AB, both sold state and both designed and handmade right here in the USA. To paraphrase its manufacturer, this amp is extremely fast, very dynamic, and delivers a very wide frequency response for a very open and musical sound. Musical indeed!