Alexus Audio 845SE Single-Ended mono amplifiers



Gregvoth.jpgAfter moving on from my long-time reference Eminent Technology LFT-8b’s loudspeakers (inefficient but wonderful) ) to the Tekton Double Impact’s (SUPER efficient and wonderful), I received word that Alex Chorine of Alexus Audio had a new pair of mono blocks for me to try out. As much as I love the ET’s, their need for high power amplification often proved challenging, limiting the range of equipment I might review. The DI’s, being 98.82 dB efficient, have offered this reviewer a wider range of products to sample; their ease of use with lower powered components has proved enlightening. Alex and his wife brought over a pair of his 845SE Single-Ended Power Amplifiers for review.

The latest addition to the Alexus Audio line, each 845SE mono block is rated 50 watts, parallel single-ended and pure Class A, As such, this pair promised to be stunning performers and they indeed were. As I put music through the pair to break them in over the next week or so, I found my foot tapping time and again, with renewed interest and enthusiasm. Usually MIA when it comes to my preferred jazz, my wife really took to them, hanging out on both sofa and bed as the music flowed. She posted a photo of one of the amps on social media, digging the glow of the larger 845’s, classic 300B and 6S45P vacuum tube compliment enhanced audio vibe on that cold winter day.



The 845’s mono blocks are indeed lookers. Measuring approximately 12-5/8” w x 17” d and 10” h and weighing in at 110 pounds each, they aren’t lightweights – they’re here for serious business. They mated well with my 4 Ohm Double Impacts (the 845 SE’s are 4, 8, 16Ω switchable), producing a noticeable synergy and wonderfully warm sound… though I do think the DI’s are a bit over warm and lack some high frequency zing. As a rule, I tend to mix tubes with solid state.

Tektonad.gifAlex is the same sweet, soft spoken, gentleman I met at the New York Audio Show a few years back. He is politely opinionated, quietly eccentric and a rather hard person to get quotes out off, preferring, I think, that his products speak for themselves. Thankfully, they do! I’ve had the pleasure of reviewing his Passive PreAmplifier, demoed speakers for review with a pair of his 833 Single Ended Power Amplifiers and used his Signature Line ONE tube preamplifier for this review while my upgraded Conrad Johnson PV-5 was out for a volume pot upgrade. While I do have a PS Audio Gain Cell preamplifier/DAC in my main rig that could have also been used for this review, I thought the PV-5 more than adequate for this review but, Alex was skeptical – the PV-5 line stage has considerably more gain that what’s considered standard today, which Alex thought could affect this review. He offered up his Alexus Audio Signature Line ONE tube preamplifier for use. It has a standardized gain of 12 dB.

I reached out to Bill Thalmann, the owner of Music Technology, Inc. who upgraded my PV-5 preamp last year, for comment. Bill told me that the PV-5 was designed at a time before the CD, when nearly every household had a turntable. Its 30 dB gain (my unit measures 32db) supported nearly all but the lowest gain cartridges available in the early days of the 1980’s. “it is what it is…” stated Bill, hence my use of Alex’s more standardized preamp for this 845SE mono block review. Though used for demo and not under review, living with his Signature Line ONE tube preamplifier for a few weeks was a pleasure; it’s one fine preamplifier.


Origin250.jpgThese 845SE Single-Ended Class A Power Amplifiers are highly capable music producers. The 845SE has a rather unique feature – the owner will always know the output tube current and if it’s necessary to make an adjustment when the amps are first turned on from stand-by and warming up. The 845SE’s require manual biasing, which is easily achieved with use of a top-mounted digital display for each tube – 2 per amplifier, one for each 845 power tube. Once taken off stand-by mode and warmed up for an hour or so, a small twist of a flat end screwdriver in each of two ports below the displays allows for easy bias adjustment. Keeping the tube biased within the 75-80 mA. range, will extend the life of the tubes up to 30 – 40%. Tubes gets weaker (exhausted ) over playing time, so it’s very easy to bring each tube back to the normal level (75-80mA.)



I readied the Memory Player Mini for some digital fun and my heavily modified Well Tempered Simplex for analog goodness. John Taylor’s family project, “2081” (Cam Jazz 2015), has become a surprise must play. I was taken aback when at my first listen of “Doozy 1,” with John’s wonderful piano introduction and the sudden appearance of the tuba providing the bass counterpoint, not to mention the vocal that appeared shortly thereafter. I didn’t expect this mix from a jazz guy and it’s since become one of my favorite listens. It’s hard to listen and not make comparisons to other artists… let’s just say I think it’s an amazingly well-done project but, with John Taylor’s passing, It’s sad that other intimate family effort like this won’t again happen.



The amplifiers added noticeable meat and immediacy to the presentation. The depth and breath of each note was full bodied and energetic. When playing this recording, I consistently raise the volume, appreciating its loose organization and surprising twists and turns. The title track, “2081,” pleasingly experimental and quite in the moment, percolated with great fun and the addition of tuba added an exciting dimension. The 845 SE’s delivered an impressive full render of this wondrous and intimate project.

In the past and an old tube system at times has left me wanting for a little shimmer, a bit more effort in the high frequencies, hence my general use of a solid state amp with a tube pre, but, overall, this all tube combination just made me smile. There was good depth to the stage, locked tight imaging and, with the piano so well integrated, it allowed the other instrumentation and vocal room to wander and shine.

bettycarter.jpgMoving on to another selection, I brought up Betty Carter’s “Feed The Fire” (1994 Verve Music Group), recorded live with a killer trio – Geri Allen, Dave Holland and Jack DeJohnette. This recording is of the best documents showing Betty’s ability to swing in her own unique way… I always boost the volume up with this one! The title track is one great jam, man – loose and bouncy, with great momentum and drive. “Love Notes” followed, a free and languishing interlude, flowing with Betty’s mojo – shifting melody and timing are her unique signature. Like the title of one of her recordings, “It’s Not About The Melody.”

The presentation was effortless with artists so gifted. Again, the 845SE’s reinforced the musical passion here, note by note, brick by brick, with generous power and space elegantly rendered. Nothing strident or forced here, just easy-going, relaxed and intimate. That describes the 845SE’s… they add the “umpf” when you need it. This live album over before you know it… it’s a great testament to how musical the 845SE’s present a source.

reiner.jpgI moved on to something different – Classic Records 180 gram vinyl reissue of the RCA Living Stereo’s “Mahler’s Symphony No. 4” by Fritz Reiner and the Chicago Symphony with Lisa Della Casa (RCA 1959, licensed from BMG Music). The stage depth was outstanding, strings were imbued with rosin and the basses full and powerful. The lilting melody playfully danced around moments of wide dynamic power as the amps provided great dynamic thrust when called upon for muscle. Notes hung in the air longer and with greater body; moments of great momentum came went effortlessly – such authority.! The 845SE’s deliver the power you need in the moment, with no strain. Dense and demanding passages were articulated with ease and finesse.

Peter Gabriel‘s third self-titled album, commonly referred to as the “Melt” was up next. This Classic Records reassured has always brought a smile to my face and every time I listen to “Intruder” chills run down my spine. With the 845SE mono blocks, this pressing was delivered with even more power and urgency, with an added sense of realism and elevated moodiness. Peter’s electronic work was built around percussion and the mallet work in a couple of the tunes was great fun, the scrapping of the electric’s round wound strings added to the eerie vibe and the resplendent bass kept my interest focused.

With “I Don’t Know How To Stop,” the mood shifted, soundstage expanded and dynamics increased. This playing of vinyl I know so well was very different than past spins – bass response was terrific, depth and resolution exemplary. The drum dynamics kept pulsing forward, pulling me further into the mix.

Sibelius’ “Symphony No. 5” Living Stereo re-issue by Classic Records was spacious and open, presented on a wide soundstage of good depth. Instrument tone was formidable and dynamics were delivered with body and panache. String tone was both rich and enveloping, horns punchy and woodwinds playful. A wonderful mid-bass conversation took place, and the basses appeared quite chatty – something I hadn’t heard with such body and agency before.

“The Palmist’s Hand,” from Anthony Wilson’s “Songs And Photographs” (2019 Goat Hill Recordings) was beautifully presented with dynamics and vitality – its melodic component well-balanced with unexpected percussive wallops. Wilson’s compositions continue to evolve and his guitar playing, always tasteful, has reached a self-assured and simplified essence, now that Anthony’s adding his own vocal accompaniment. Less is definitely more.

“While We Slept,” listened to as a 24-96 rip provided by Michael Fremer (, piqued my interest in this project – searching the rest of the album out proved quite rewarding indeed. The album is full of well-placed dynamic accents that drive the effort along fluidly, while its simple, sweet arrangements work on your heart. The 845SE’s delivered these dynamics without stress or strain – feeding the musicality of each moment with finesse and muscle when called for. There were growls in those digits, contrasting the title track’s folky simplicity with bold unexpected accents. Even listening off axis while typing some of these notes up, the dynamics and headroom provided by these mono blocks was undeniable and exhilarating.

Upwardonward.jpgReady for some cookin’, I cued up One For All’s “Upward and Onward” (2009 Criss Cross Jazz). “D’s Blues” pounded out of the Tekton’s with power, punch and drive. The song that followed dialed the pace back to a ballad tempo; bass was strong, centered and, with the percussion, the rhythm section gave the other players room to stretch out, with nice body to the horns. “We All Love Eddie Harris” picked the pace up with a solid groove, good solid imaging and strong upper bass. There was no wanting for headroom here.

The highlight for me might be One For All’s rendition of “John Coltrane,” with its sweet ride cymbal ring, bass bloom, sonorous trumpet and brooding sax which really lit up the groove. The piano body was warm and well integrated with the other instruments. Taps on the center of a cymbal held a strong place in space.

Lastly, I spun the newly-pressed and recently received “No Filter” by Jerome Sabbagh and Greg Tuohey. This is the second of Jerome’s Kickstarters I’ve backed and I can say it’s always a thrill to spin a newly-minted pressing from a project one has so closely followed. The density of the music hits you first – it’s thick and meaty, like a nice sauce, with rich textures and overtones and replete with rewarding musicianship…. but all was not all roses – overall too dark and dense for my taste with this particular mix of components. The 845SE’s show warts and all, they give you what you give them.

The Wrap

I wish the 845SE’s were staying. At $16,995.95 price, they should be considered one heck of a deal – it’s a price I consider affordable for what is delivered by these hand-built, single-ended class A wonders. To my ear, the 845SE’s are Alex’s are his best amplifiers to date. When I told him this, and he responded “I think so too.” A man of few words, Chorine has achieved something very special here. Do give them a listen!



greg voth   


Spcifications: Alexus Audio New 845’s mono blocks

Direct Price: $16995.95

845 parallel single ended Pure Class A monaural power amplifier

Model: 845SE

Rated power: 50W @1kHz, 5% THD

Frequency response: 8Hz ~ 50kHz (+/- 1db. @1W)

Input / Impedance: RCA unbalanced / 100kΩ and XLR balanced

Output: 4, 8, 16Ω (switchable)

Noise: Lower then 0.3mV

Vacuum tube compliment: 845 x 2, 300B, 6S45P

Power consumption: 350W

Dimension: 320mm(W) 370mm(H) 458mm(D)

Weight: 50kg

Alexus Audio

Alex Chorine


10 Year warranty All Products 

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