Review: Octave V 16 Single Ended Integrated/Headphone Amplifier

Dec 06, 2023

The Octave V 16 is, as its name says, a single-ended design running a pair of KT120s (or KT150, KT88, or 8550) in triode mode for about 8 Watts of output power per channel, i.e. more than enough power for a few pair of speakers on hand in Barn.

More than enough power for the Barn resident DeVore O/96 (review), the review Zu Audio Definition 6 (more info), and the recently reviewed Living Voice R25A. Regular readers may remember my first encounter with the V 16 at Goodwin’s High End, where salesmen par excellence Mal Becker pointed out that the tower of power, my nickname for V 16, made a lovely mate for the O/96.

Here’s the thing about great hifi sales people, especially those who’ve been at it for decades like Mal—they know what they’re talking about because they have more experience than most other humans when it comes to building systems. Way more experience than any reviewer, at best we can review 50 or so pieces of gear a year, and way more experience than your regular hifi buyer. Them’s just the facts so when someone like Mal says something like the Octave V 16 works really well with my DeVores, I listen.

Experience also suggests that matching an amp to a speaker requires listening. One easy example is the Klipsch Corwall IV I reviewed back in 2022. If you look at specs, 102dB (@ 2.83V / 1m) with a nominal 8 Ohm impedance, you might think, “Cool! I can use my 2A3 amp with power to spare!” And I might’ve thought the same thing if I didn’t know better because the Cornwall IV, and most of the bigger Klipsch speakers I’ve heard, need more power than a few Watts to wake up that 15” driver and make it sing in harmony with everything else. My favorite amp for the Cornwall among the amps I had on hand was the 225 Watt ModWright KWH 225i Hybrid Integrated Amplifier (review). Even actual easy to drive speakers like the O/96 can make some great amps sound kinda blah and my best guess is the DeVore’s higher than typical 10 Ohm impedance has a lot to do with it.

The great thing about buying a hifi is we don’t have to guess about amp/speaker mating rituals because we can try them on for size, or rely on hifi salespeople who know about such things because they’ve heard more systems than you or I ever can or will. Note: HiFi shows don’t count.

Octave Audio is based in Karlsbad, Germany and the company’s history dates back to 1968 when Andreas Hofmann Sr. founded the transformer winding factory Hofmann. Andreas Hofmann took over the Hofmann company from his father in 2000, giving it its new name—OCTAVE Audio—with a focus on the tube-based electronics he’d been designing and building since the 1970s.

The Octave V 16 Single Ended Integrated/Headphone Amplifier uses a highly specialized magnetic-field compensated output transformer designed, developed, wound, and meticulously crafted in-house. Octave explains that this special transformer remains linear down to 10Hz, solving one of the issues with some single-ended amplifier’s lack of bass. On the other end of the frequency response scale, the company claims an upper end reach up to 80kHz (@ 5 W 0 / -3 dB) By means of specific driver stages and an optimization of the feedback.

The tubes in play include 1x ECC 82 and 2x EF 800 in input/driver stage and the aforementioned pair of stock Tung-Sol KT120s. Dynaudio North America, Octave’s US distributor, also sent along a pair of Tung-Sol KT150s and I’m very happy they did as I preferred them to the KT-120s in every way by an easy and obvious margin.

Another option that was included in the review package is the Octave Black Box Capacitance Power Storage Device. I’ll let Octave explain:

The dynamic and tonal stability of an amplifier is strongly dependent upon the stability and capacity of the power supply, therefore the Black Box and Super Black Box were developed as external upgrades to the OCTAVE amplifiers’ power supply storage capacitors by increasing their capacitance by a factor of 4 (Black Box) or 10 (Super Black Box), respectively. This is a tremendous benefit if the speaker is difficult to drive. Loudspeaker efficiency is made less critical, while the amplifier is enabled to handle speakers with minimum impedances as low as 2 Ohms.

The power supply capacitance increase realized via use of the Black Box or Super Black Box stabilizes current delivery and reduces the impedance interaction of the load. This improves dynamic range, separation, depth, soundstage size and articulation, rendering the musical reproduction clearer throughout the entire frequency range. The amplifier remains unaffected by mains variations and interferences due to the noise filtering characteristics of the capacitors.

Interesting, no?, and going some way in describing an important aspect of the amp/speaker interface. Nice!

The V 16 sports 3 inputs (2x RCA, 1x XLR), a pair of speaker binding posts, a switch to engage/disengage a subsonic filter (cutoff frequency is 22 Hz / – 3 db) for use with phono preamps that do not offer one, IEC inlet, and a connector for the Black Box’s umbilical cable.

As you can see in its name and front panel, the Octave V 16 is as much a headphone amp as it is an integrated amp with dual headphone jacks (6.3mm, 4 pin XLR connected in parallel so can use ‘em both at the same time) that accommodate single-ended and balanced ‘phones. There are six buttons across the front from left BIAS High, OUT High, Loudspeaker, and INT (input) 1-3. The BIAS button, when engaged and lit, runs the output tubes at their maximum idle current for use with low impedance speakers (4 Ohms). When not selected, the idle current of the output tubes is reduced for use with speakers with an impedance higher than 4 Ohms. OUT High (max output level of 9 V) is recommended for loudspeakers and high impedance headphones, OUT Low (max output level of 4 V) is recommended only for high efficiency headphones. Last but not least is that nice chunky volume control knob that offers a Goldilocks amount of resistance—not too loose or too tight.

When you power up the V 16, a soft start circuit engages for about a minute—The V 16 Single Ended input- and output-tube-heaters as well as its high-voltage-rails are logic controlled to ensure that the operation of the output tubes as well as input stage voltages are constantly monitored and controlled by the Power Management System to protect the vital internal parts (tubes, rectifier, electrolytic caps, switches, etc.) against excessive turn-on current. There’s also a built-in protection circuit to keep the output tubes safe from overload or current surges.

The included remote is my favorite kind of remote because it has but two control buttons. No manual required.

I wonder if you already have a sense of my thoughts about the Octave V 16 from a build quality perspective? Between the images, mine and Octave’s, and all those words? I bet you do have a sense that I loved living with the Octave V 16 as an object, as a lovely tower of power, for its superb build quality, its unusual vertical-ness, and for letting those output tubes stand on high. If you like the looks of the V 16 in pictures, you’ll love it even more in person.

The V 16 also performed flawlessly during its 2.5 month+ stay and it do not make the slightest sound, not a peep, nary a hint of hum, when not playing music through any of the speakers it got to play with, not even through the Zu’s 101dB (SPL 1W,1m) load.

And as you may have already figured, Mal at Goodwin’s was right—the V 16 made the DeVore O/96 sing oh so sweetly with effortless endless drive, unflinching control, and an addictive fluid clarity that made music, all music, feel devoid of coloration while sounding as rich and lovely as I’ve had the pleasure to hear. A single-ended amp that tickles both hemispheres, left and right.

When an amp/speaker combination gels so well, so perfectly well as is the case with the Octave/DeVore paring, my thoughts during the review period are overwhelmed with what I can’t wait to hear next. I’m not talking about sound effects excitement that makes me jump from track-to-track without listening all-the-way-through any (ick), I’m talking about album after album (after album) kind of listening, the kind of listening that turns all of my attention to the music being made, to any and every aspect of the recording in play. Clean clear delicate powerful music.

Black Country, New Road’s 2022 Ants From Up There is a gem of a record for its angular unexpected broken rhythms, a genre-defying box of tricks with horns blaring, guitars churning, all angular and math-rock-tinged, words I used when I first wrote about this record along with The album, on whole, is filled with twists and turns and a breadth of sound that only a seven piece can muster. Witty lyrics, grace, and humor all perfectly in sync. Brilliant. Moving from gentle piano, horns, strings, and vocals to hard crush post-punk, Ants is a great workout for any and every mood with touch points for the best and worst of ‘em. What a record, and their last with lead singer and guitarist Isaac Wood. Sigh.

All of this musical stuff, the sudden starts and stops, the acoustic array of sounds, the amplified mayhem, offer a rich sonic and emotional journey. The Octave/DeVore system, with the able assistance of the Auralic ARIES G1.1 Streamer (review) feeding the totaldac d1-unity (review + full system details), made this amalgam come alive in Barn, filling it and me with a carny atmosphere, the musical proceedings teetering on the verge of breakdown. A more solid and color-right presentation I cannot recall, the Octave V 16 felt more like a music propelling machine, an over-powered engine sending the DeVores ample juice to convert current into pure sound energy. Effortless perfect clean power.

I’ve already shared that the Technics SL-G700M2 in that review, playing “Midost” from Marc Ribot’s Ceramic Dog’s Party Intellectuals filled the Barn at levels as loud as I ever care to go, and taking into account the 7,560 feet3 listening area of volume, the Octave’s 8 Watts paired with the O/96 should satisfy most people in most rooms, at least those people who care about keeping their ears undamaged.

Ida’s 2000 Will You Find Me is a slow gentle album headed by the vocalizing of Elizabeth Mitchell (also on guitar and Wurlitzer), Daniel Littleton (also on guitar, Wurlitzer, and organ), and Karla Schickele (also on bass, piano, and organ) with the help of a bevy of musicians playing violin, viola, piano, cello, double bass, percussion, Melodica, organ, electric piano, and more. The Octave/DeVore combo gave full voice to each element laid out in an easy to ‘read’ space that had no ties to the speakers in terms of their origin. A clean, clear picture.

Perhaps its force of habit or worse a tired cliché, but I am tempted at times to ascribe colors or color temperatures to an amplifier’s sound—warm, cool, golden, sepia, etc. It’s also very easy to do, which typically means the observation doesn’t hold much weight. 300B-based amps’ golden glow, an 845s brutish bronze, the lovely rose hue of the eminently likable EL84. As if every amp with a 300B, 845, or EL84 sound exactly the same, which is no different than suggesting that everyone from NJ has the same accent (we don’t).

That being said, the Octave V 16 is among the clearest sounding amps I’ve had the pleasure to spend real time with. This is especially so when running the Tung-Sol KT150 output tubes, by far my favorite over the stock Tung-Sol KT120s, and when using the optional Black Box Capacitance Power Storage Device. With the Black Box connected, music sounded more tidy overall, with improved resolution and better bass control. Without the Black Box, things got a bit looser and less well defined, which to my mind makes the Black Box more than worth its asking price. And the real kicker in terms of emotional connection to music is the V 16 also sounds harmonically right—not too lush, not too thin (Goldilocks makes another appearance).

Dirty Three’s Horse Stories from 1996 features Warren Ellis on violin and bass, perhaps better known for his dreamy intense soundtrack collaborations with Nick Cave or as Cave’s alter ego as part of the Bad Seeds, Mick Turner on electric and bass guitars, and Jim White on drums. This music brings to mind, to my mind at least, the country, a dusty barren land, filled with endless empty vistas and looming danger. The band calls Australia home so maybe memories of Werner Herzog’s Where the Green Ants Dream and the original Mad Max have inadvertently merged and painted their landscape over this soul stirring music. In any event, lovely in every way.

With this at times hard-driving music, I can see Warren Ellis twisting and churning with snapped bow strings flying as wildly as his hair and beard, the Octave V 16’s wonderful sense of drive, clarity, and color (the colors of the instruments at play) drawing me well in, erasing the things in front of me by replacing them with Horse Stories’ places and spaces. Yum.

I had to do it. I just had to take the Octave’s headphone amp for a spin, lured in with promises of a more intimate yet equally compelling experience. With the trusty AudioQuest NightOwls wrapped around my head, I let the early release tracks from yeule’s upcoming ghosts, I pre-ordered the LP on Bandcamp, bring me to more ethereal and strange places.

It should come as no surprise and much delight that the Octave’s superb grain-less clarity and refined just-right colors came through loud and clear through the NightOwls. I could see myself getting into headphone listening with the V 16, something I rarely feel so rarely say, with the bug bite of what other ‘phones should I try already itching away under my skin.

And what about price, value, and output power? You know, the argument made by some people that it’s not sensible to spend $X or more on an amp because it only puts out Y Watts. This thinking makes less sense than suggesting a book is not worth reading if it weighs less than 10 lbs. Less sense than that.

I have Mal at Goodwin’s High End to thank for initially putting the idea for this review in my head and I’m not all surprised that I found myself nodding my head “Yes” as I was listening to it drive the beauty out of the DeVore O/96, just like Mal said it would.

While I focused on the O/96 pairing, the Octave V 16 also proved a lovely partner to the Zu Definition 6 and the Living Voice R25A, its strengths traveling along with it regardless of the partner in play. If you own speakers that have similar friendly-to-drive manners and also enjoy headphone time and you want your music coming out of both to sound clean, clear, delicate, rich, and powerful—that tickles both hemispheres, left and right—hear ye the Octave V 16.

Octave Audio V 16 Single Ended Integrated/Headphone AmplifierPrice: $10,000, optional Black Box Capacitance Power Storage Device: $1200, Tung-Sol KT150 upgrade: $250/pairCompany Website: Octave Audio

Specifications

Power Output:

High Mode: 2 x 8W RMSLow Mode: 2 x 5W RMS

Frequency Response: 10 Hz – 80 kHz @ 5 W 0 / -3 dBTotal Harmonic Distortion: 0.5% bei 3 W an 4 OhmSignal-to-Noise Ratio: – 110 dB / 8 WLoad Impedance Loudspeaker: 3 – 32 Ohm ( BIAS High – Low )Load Impedance Headphone: 6 – 2000 Ohm ( OUT Low – High )Gain: 26 dBConnections: Inputs: 2 x Line Level / RCA, 1 x XLR Line LevelOutputs:

1 x Loudspeaker output1 x Headphone output 6.3 mm jack1 x Headphone output 4 pin XLR1 x Regulated preamplifier output RCA (optional only ex factory)

Preamplifier

Input Sensitivity: 400 mVInput Impedance: 50 kOhm / Cinch, 25kOhm / XLRCrosstalk left/right: 40 dBCrosstalk Input/Input: > 90 dBOutput Impedance Pre Out: 40 OhmMax. Level Pre Out: 5 V RMSTube Complement Preamplifier: 1 x ECC 82, 2 x EF 800

General Facts

Power Consumption: 120-200 W idle, 200 W @ full powerWeight: 19 kgStandard Accessory: Power cord, IR-Remote Control, Allen key for removing the coverMain Fuse: 230/240 V main: 2,5 A slow-blow type H