TUBE JOURNEY
Smart design and high output valves deliver thrilling sounds from this ‘Special Edition’ German amplifier.
This German valve amp achieves 120W of power. Read our glowing review.
If Octave is not a brand you know, you’re probably not alone — yet it has been making amps under this name since 2000, and for a quarter century before that under a previous generation, having been founded as a transformer winding company in 1968 by the father of the current Executive Director and Chief Designer Andreas Hofmann. Octave’s products are handbuilt in the village of Karlsbad in Germany, where each amplifier gets not only quality control but a 48-hour durability soak before leaving the building.
It’s not hard to like Mr Hofmann’s designs. A fundamental philosophy is that while valves have that speed advantage and the delightful dichotomy of “musical” even-order distortion and soft clipping, Octave introduces transistor circuits for control, monitoring and protection. There is soft-start technology and a controlled “power rise”, careful stabilisation and an auto-standby mode available which shuts down the valves after 10 minutes, which the company claims can deliver them significantly longer life (five years minimum for the output valves, it suggests).
With all this kept out of the audio path, the only disadvantage we can see to such a ‘hybrid’ is that unlike pure valve designs, the V 80 SE might not work after a nuclear attack and EM pulse. Darn.
Equipment
The V 80 SE was, as its name suggests, intended to be a tuned-up version of the V 80, but Octave’s engineers apparently got somewhat carried away and delivered a significantly new design, with a new-generation driver stage using a push-pull pentode system, as well as a new headphone amplifier. We had our high-sensitivity speakers ready to use with this valve amp, but given it’s rated at a full 130W RMS per channel operating from 20Hz to 80kHz, that’s less the requirement than with most valve amplifiers; indeed Octave says this power amplifier enjoys excellent load stability so that “neither the impedance nor the efficiency of the partnering loudspeakers will affect the V 80 SE’s sound”.
This is also the company’s first outing using the heady power levels of KT150 valves, which are the first thing you uncover when opening the significantly heavy box — and for once in our reviewing lives we sat down with the manual (and white gloves) rather than simply getting into it. Despite Octave’s deliberate efforts to make valve amplification easy, these are still glass vacuum tubes deserving of respect!
The supplied manual was in German, so we got the English version up online, and followed the instructions. We removed four little Allen bolts (see pictures), lifted off the valve guard, then donned the white gloves to firmly insert the four gorgeous KT150s. Power on.
Performance
One of the V 80 SE’s management (and life-saving) techniques is a ‘soft start’, which takes about a minute in normal use. But at initial set-up you wait five or more minutes for the valves to warm up before checking the bias settings. This is made a wonderfully simple procedure here (compared to some where you have to get inside the amplifier and fiddle with screwdrivers alarmingly close to the high voltages involved. Here, instead, you turn the smaller right knob to ‘Bias’ and then look at the rows of LEDs that illuminate on the Octave’s front panel display (bottom right picture). These indicate either over or under biasing — orange when warming up, a row of greens if all is well, red if over biased. You insert the small screwdriver under any non-optimised LED, and turn until you get the green light. It’s super simple and perfectly safe. On our unit valves 2 and 4 proved spot on, valves 1 and 3 needed a tweak, though we adjourned for coffee and a half-hour break first, in case this new amp just needed some more time. Just a little, as it turned out.
This easy system also simplifies substitution and biasing of other compatible output valves; the company doesn’t recommend using low power valves like KT66 or EL 37s, but mid-power (e.g. KT 88s) can be used with the bias set to ‘low’.
Then we encountered what was for us its highlight — delivering vinyl. The phono stage on the V80 SE is an option, and comes dedicated to either moving magnet ($POA) or moving coil ($999) curves, not switchable. Distributor BusiSoft AV kindly supplied a V 80 SE with a moving-coil phono stage though, shamefaced to relate, we had no moving-coil cartridge to hand. So instead we used our usual Musical Fidelity phono stage and preamp in order to connect our Thorens turntable, taking advantage of one of the Octave’s points of versatility to do so. If you switch the righthand small knob to what Octave calls the ‘Extern’ function, you can use the V 80 SE as a two-channel power amp, in this case with our separate preamp plugged into the “Master Input”. This doesn’t, however, head at full level direct to the power amps, since the Octave’s volume knob is still in circuit — certainly safer, but leaving you a choice of two volume controls. The manual says “When using this option, you should generally set the volume control on the V 80 SE to maximum and adjust the volume with the external preamplifier.” It seems curious to suggest crushing the waveform at source in this way (also raising the noise-floor of the not silent V 80 SE), unless perhaps the V 80 SE’s performance is compromised at low levels — but this is not usually, and certainly not here, an issue with valve amplifiers, quite the reverse. So we went the other way, giving the V 80 SE a full-level direct output from the preamp/ DAC and having the usual control range available using the Octave’s volume knob.
While the knobs on the V 80 SE are nicely weighted, volume control is most conveniently enjoyed using the supplied heavy two-button remote. (Yes, just two buttons, volume up and down — that’s enough, isn’t it? What else do you plan to do?) The response of the buttons is perfectly smooth, even through transition from nudging down to ramping down, and the fade occurs sufficiently fast to be used as a mute if, say, the phone rings.
You might just want to park that call, mind you, given the heights of delight this amplifier conjured from the grooves of the very first disc we randomly plucked, side three of a 2-LP Morricone compilation, and from Once Upon A Time in America to The Falls from ‘The Mission’, there was a scintillating spiritually musical delivery of every element; the combination of richness and clarity to the strings was glorious. Ruthlessly revealing too — indeed on the climax of The Falls the difficulty of cutting the complex and rich bass to the inner grooves was clear to hear. It barely dented our enthusiasm.
With sound this good, we were quick to head to our Led Zeppelin 180g remasters. We span up the main disc of ‘Zep II’.
Dear God. The size of the bass on the intro to Moby Dick; the weight and speed of Bonham’s kick drums.! If you’re one who generally skips the Moby Dick drum solo, well, we listened to it three times over here, partly for the dynamics and depth that made it real at a reference level, and partly to confirm an edit we’d never noticed where the level jumps up and the left kick drum goes from perfectly recorded to slightly over-modded. New discoveries on a Zep album? Music geek heaven.
Since with all this we were using our usual phono stage and preamp, this showed the merits of the power amps in particular. We have had large reserves of power to hand before, but none that so well matched the ability to deliver such spectacularly snappy dynamics with such authority. Some can turn the tap on quickly but not off; this was slam without overhang. Riveting listening.
With everything firmly warmed up by now, we rechecked the bias. Still perfect.
Of course, one downside of this amplifier is the lack of a DAC — there are no digital inputs, no USB, no optical. But we had our usual Musical Fidelity USB DAC wired into it, and listened to all kinds of files, high-res and low, both playing through our own preamp and through the V 80 SE’s own unbalanced CD input.
Again the sound was solid-edged in presentation, the piano entry percussive on Diana Krall’s Alone Again Naturally, a delightful delicacy to the brushwork and her voice velvet with its sibilants impeccably human, effs and esses with no emphasis, no spit. It was still an unflappable sound, just occasionally thinning a vocal — McCartney on Every Night, Glenn Shorrock on Reminiscing. We had it paired with Dynaudio’s Special Forty speakers for a while, and the imaging was downright forensic, every instrument on its axis — those panned harmonies on Reminiscing a spatial thrill, if just a bit light; we found the performance more convincing through the MF preamp to the Octave’s output stage. We were just loving that output stage.
A higher Octave
We remembered, then, that the V 80 SE can be upgraded with one of two levels of Black Box. That’s what they’re called — the Black Box and the Super Black Box (pictured above left). Both upgrade the power supply by adding additional capacitance, the Black Box ($1699) said to quadruple the original farad count, and the Super Black Box ($3999) to multiply it by ten.
Well we’d been sent a Super Black Box, so we plugged it in alongside... you couldn’t be putting it on top, since the Octave runs hot — not quite hand-burning hot, but pretty close. (The cage is a safety necessity, as well as a legal one.) The Super Black Box requires no mains, looped in via a multi-pole connector on a flying lead to the back panel. It’s not something you can easily A-B in a listening session, and it will be most useful for assisting the V 80 SE in dominating any difficult speaker loads at times of high density and dynamics. We found it didn’t vastly alter things with our sensitive horn speakers, though with one particularly stubborn stand mount pair it seemed to add an extra level of confidence to performance, an unflappability when punching out dynamics and handling high density music.
Headphone lovers will suffer a bizarrely placed headphone socket, positioned between and below the speaker connections — convenient for ad hoc use it ain’t. But there’s a three-position DIP switch on the back — no headphone output, headphone and speaker output, or just headphone output. So you can have a 6.5mm extension lead permanently plugged in at the back, then use this switch to turn it on and off. (Why a position for both? Some people like it that way, enjoying the detail of open headphones and the physical impact and room effect of speakers. It works best with bass-light and open designs, like Sennheiser’s HD 800.) And we should thank Octave for including a headphone socket at all — it’s not unusual to omit them on valve amps, and indeed this one uses a solid-state output stage, and one which has immense headroom; our AKGs are neither especially high sensitivity nor low impedance but we kept them firmly in the first third of the dial, enough to enjoy the V 80 SE’s preamp performance via that output.
As for Ecomode, we powered things down and up manually most of our time with the V 80 SE using the rocker switch on the left side of the glowing chassis — the auto ‘switch off’ wasn’t on by default when the amp reached us. But after leaving it glowing away for a couple of days by mistake and returning to rather over-radiated room warmth, we engaged Ecomode via the second DIP switch on the back, so the amplifier’s valve circuitry would be turned off during perceived breaks of more than 10 minutes in playback. That’s a pretty short break, with the price of a minute’s Soft Start wait when you return, but the reward is longer valve life, less heat, and a lower power bill from those forgotten moments, since its normal idling consumes 180W while the Ecomode consumes 30W — it’s not a full standby mode, as the headphone output and ‘record’ circuits remain active… 30W is still a good few lightbulbs’ worth, so we switched it off entirely after listening. If we remembered.
Conclusions
Great joys from the Octave V 80 SE during its stay, driving a series of visiting speakers as well as our usual suspects. While the Black Box concept will be useful for those pairing it with demanding speakers, for us the versatility of conjoining of a vinyl source and separate preamp with the Octave output valves proved particularly divine, creating true hi-fi magnificence of reality at the highest levels.