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This review first appeared in the December 2008 issue of fairaudio.de and can be read in its original German version here. It is herewith translated and presented to an English-only audience through a mutual syndication arrangement with fairaudio.de. As is customary for our own reviews, the writer's signature at review's end has a link below it to his e-mail should you have questions or feedback you wish to send. All images contained in this review are the property of fairaudio.de or Octave. - Ed.


Reviewer: Ralph Werner
Sources: analog - turntable - Acoustic Solid MPX; tone arms - Phonotools Vivid-Two, SME M2 12-inch; cartridges Denon DL-103, Ortofon MC Rondo Bronce, Shelter 501 MK II, Zu Audio DL-103; digital - audiolab 8000CD, Fonel Simplicité
Amplification: integrated - Lua 4040C, Myryad MXI 2080; preamp - Funk LAP-2, Octave HP 300 MK 2; power amp - SAC il piccolo monos
Loudspeakers: Audiaz ETA, Volent Paragon VL-2, Sehring S 700/701 SE, Zu Audio Druid MkIV, Zu Audio Presence
Cables: low-level - Ecosse Baton + Symphony, Funk BS-2, van den Hul Integration Hybrid, Zaolla Reinsilber; phono – fis Audio Phono, WSS Silver Line; high-level - Ecosse SMS2.3, Ixos 6006 Gamma, Zu Audio Libtec
Racks & Stands: Creactiv, Taoc, Liedtke Metalldesign Stand
Review component retail: €6.800 (Phono MM +350 Euro, MC +400 Euro)
Standing aloof
As sexy as those valves may glimmer and glow on Octave's home page, little about the brand lends itself to cheap valve clichés. In fact, Octave chef Andreas Hofmann is mostly known as a killer of them. That's arguably overreaching a tad but he's clearly unwilling to participate in fashion trends and hype. Those he shrugs off with the occasional wonderfully deft dismissal but overall, he probably plainly doesn't care.


Here's a sample: "The bass of many valve machines is mostly tonal mud with little correlation to the original. In many ways, I react to it as psycho sound, meaning it sounds quite good but always identical. That's not the sound intrinsic to the valve. It's the sound intrinsic to the circuit where limitations of relatively antiquated solutions are branded desirable attributes. That might seem a bit provocative and I don't mean to downplay all the qualities of classic tube gear. Still, there's no sense to whittle away forever at vintage circuits. At least not to me." Well put. Today's tester is Octave's biggest integrated, the V80, a hopefully entirely unmuddled proposition.

Concepts in quotes
Octave has made valve amplification -- preamps, power amps and integrated amplifiers -- for a quarter century though the company history begins in 1968 when Hofmann senior catered exclusively to industrial applications. His clients worked in the ultrasound sector and demanded specialized transformers. Connecting with music/hifi usage would be for his son during the 80s while building squarely on the technical experience already garnered in the ultrasound sector. The acquired savvy on how to develop application-specific transformers certainly must have fit like a glove.


"No matter how good they might be otherwise, we can't run universal transformers from various vendors as they would constitute unacceptable compromises." Thus all Octave iron is developed and rolled in Karslbad but the 'made in Germany' tag really applies to the product as a whole. What then might be cherished preconceptions the usual valve lover has to relinquish with Octave? First off, bye-bye triodes. Octave relies on pentodes exclusively. To avoid confusion, "certain manufacturer run pentodes in triode mode which, to my ears, creates zero advantages, sounds bad and pushes the valves beyond certain stress limits."

'Single-ended' is the next concept Octave candidates will have to chuck since Herr Hofmann's output stages all run in classic pentode push/pull mode and not in ultra-linear. The latter enjoys the shinier reputation in certain quarters whereas Octave finds pentode operation infinitely more stable. Then zero feedback flies out the window: "Zero feedback proposes the illusion of magically transcending certain inherent challenges of amplification technology. That is true to a certain extent but it also creates new problems with specific sonic consequences. Hence zero feedback itself is just another compromise. The very low damping factor and poor control of the amp over its inductive load creates potent limitations in choices of suitable speakers. Normal multi-way designs may not apply. Thus we find it more sensible to optimize the push-pull amplifier concept instead."

According to Hofmann, no truly novel valve circuits are left to discover. Refinements are possible which he certainly pursues but more relevant to his machines are peripheral enhancements surrounding the interface of circuit and valves. This means the power transformer with the complex windings tube amps require (driver and output tube filaments, high voltage supplies for driver and output stages, cathode supplies) and proper grounding schemes. But Hofmann considers as peripheral also the power supply whose status he calls the Achilles heel of many if not most valve amps. He dislikes popular choke filtering for its high impedance which will always collapse under current-heavy bass transients to induce broadband power supply instabilities. That creates phase shift modulations and essentially represents an out-of-control feedback mechanism between loudspeaker load and amplifier despite so-called zero feedback circuits: "Our actual development pursued the notion that if an amplifier is expected to remain stable, i.e. sonically load-invariant within its power delivery window, one needs a fully decoupled power supply since 'load feedback' otherwise affects a circuit's various stages. Such kick-back is always delayed in time which sonically means, defocused as though the sound mixer had added artificial reverb. In extreme cases, the output stage simply mumbles incoherently in the bass whenever a particular transient hits with sufficient intensity."


But Hofmann is just as opposed to feedback über alles to cheaply compensate for power supply insufficiencies. Instead, the heavily stabilized power supplies of Octave amps allow rather modest (ca. 10dB) NFB. If you now expect a killer-sized power trafo, the V80's is quite substantial but for its 440-watt RMS rating, bigger has been spotted elsewhere. Good-bye mondo mythos too. Ditto for beer-can capacitor fetishists. Rather than indulge in extreme capacitance posing, Herr Hofmann stresses that his suppliers Epcos and Frolyt are among the world's foremost and that it isn't simply a matter of cubic inches (which would be easier to communicate) but the speed whereby stored energy is made available; the related charge times; and the long-term stability of electrical parameters.

To conclude: "The sonic advantages are subjective of course but I believe in this instance that a few things can be objectified. Technically I'd say that I'm an extremist who has to pursue a concept to the very limits of the doable. Only then can one determine whether it was sensible. If you stop short, you cannot make any statements on advanced possibilities in the High End. I recently read a website statement of a Japanese speaker maker who decried the loss of anything between original and playback. This maker designs speakers to go to 9Hz. I had to grin but also confess that the man was right."
Octave V 80
The test sample was the no-phono matte silver edition. The MC phono options adds 400 bills to the €6800 base fee, MM goes for 350. You must decide on MM or MC since both aren't available together. Without blushing, Octave's V80 must be called exceptionally featured at least for a tube machine. The fascia sports four mirror-imaged knobs. The big one hard left selects between four line-level inputs, with CD1 being balanced, the others single-ended; plus the optional phono. To listen to tape (input 5), the small control to the right gets turned to tape. Recording is possible independently. The third position, 'center', allows for the insertion of a multi-channel receiver which skips the V80's attenuator to control volume through the receiver.
The big right knob of course controls volume. The smaller left knob points at 'linear' during normal operation while the 'extern' position separates the V80's pre and power stages via relay. This allows

• Running the V80 as preamp into an external power amp by connection to the 'master out' sockets accordingly or...
• Running the V80 as power amp with an external preamp or equalizer, using the 'master in' inputs.


One may also bi-amp with an external preamp if that offers twinned pre outs (and if you have a second power amp to slot beside the V80). More likely is a bi-amp scenario wherein the V80 serves as preamp plus power amp and one simply adds the second amp via the pre-out which is possible in the normal 'linear' position. Needless to say, that pre-out is also handy for potential subwoofer applications. Around back, we find three unusual items besides the rock-solid RCA, XLR and high-level sockets:

• The headphone output does indeed hide here somewhat impractically though I'll admit that the necessary 'hole' upfront wouldn't do well. The small associated toggle determines whether the transistorized can amp runs with the speakers, solo or not at all.
• Another toggle activates 'ecomode' whereby the machine is triggered by 10-minute silence to enter stand-by, leaving the tape loop and headphone outputs active. This feature provides peace of mind should the amp remain powered up by mistake. It also increases longevity of the power pentodes and capacitors. Additionally, ecomode consumes a mere 20 watts. When music signal reappears, the tube-friendly soft start automatically ramps up the machine within 30 seconds.
• Adjacent to the power IEC inlet sits the 'Black Box connector' which links to the above-mentioned optional power supply capacitance multiplier.


Back to the front to dial in power tube bias. That feature has been expertly addressed to not require a multi meter. Precision opamps handle the required pulse taking with 0.3% accuracy. And, adjustments occur from the front and are idiot proof due to small LEDs.


Just because you detect green and red lights doesn't suggest I'm blind. For KT88s that's the correct setting whereas EL34s want yellow/green. The basic layout inside is straightforward and segmented as expected. The transformers live in the back, with the yellow-potted power trafo to the left and the output transformers to the right. The output section is central and the preamp stage gets its own board upfront. A few words about the remote. It controls volume and nothing else. That's okay but a mute button wouldn't have offended. This is a learning remote and about time a manufacturer provided one. Nothing rattles me like searching for a stupid wand - and one always does. Duly enthused, I quickly programmed Octave's wand to also control my CD player. And it worked. At least with the player. I must have hit a few wrong buttons as well since Octave control vanished. Argh. But hey, I now had a backup in case the original CD remote disappeared. Super.
I received two boxes from Karslbad, the bigger one containing the V80, the smaller a box filled with capacitors. No loose bits mind you but the Super Black Box external power supply add-on which is available for Octave's RE280Mk3 and MRE130 amps as well as for its V70 and V80 integrateds. To nip impedance-critical loudspeaker concerns in the bud, Octave promises unassailable stability. For an extra 2.350 bills. The (by a factor of 5) less 'capacitant' simpler Black Box commands 770 euros. The amp itself ships with a quartet of 6550 or KT800 output tubes (plus a spare) and a learning remote; a hex key to dismount the tube cage (the power pentodes need to be inserted, the small tubes arrive pre-installed) and a small screw driver for bias adjustments. Of course there's also a power cable and comprehensive owner's manual. High-profile reviewers, upon insistence, also receive additional toys by way of an EL34 set plus two alternate type ECC81/ECC802 drivers (stock drivers are JAN-6072).


Sound
One can play match maker until death does them part, for example when being sent an amp only to leash it to eight different speakers while the amp allows the option of with/without external box plus a choice of driver and output tubes. Then the danger looms of missing the base line for the details altogether. On that account, I was duly jollified about the admittedly crass assessment by a speaker designer: "Octave? Sounds like transistors but far randier." Which leaves little to add save that this bonmot becomes more poignant even in the reverse, i.e. when transistor is replaced by valve.