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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, PureMusic 1.89b in hybrid memory play with pre-allocated RAM and AIFF files, hog mode and 24/176.4 NOS-style upsampling; Audirvana 1.4 in direct/integer mode, Metrum Hex, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2s
Preamp/Integrated: ModWright LS-100 with Psvane tubes, Esoteric C-03, Bent Audio Tap-X, TruLife Audio Athena, Bakoon AMP-11R, Nagra Jazz [on review], Thrax Audio Dionysos [on review]
Amplifier: First Watt SIT1, FirstWatt SIT2, ModWright KWA100SE
Speakers: Aries Cerat Gladius, Boenicke Audio B10, Zu Druid V, Zu Submission, AudioSolutions Rhapsody 200
Cables: Complete loom of Zu Audio Event, KingRex uArt USB cable
Stands: Artesania Esoteric double-wide 3-tier with TT glass shelf, Rajasthani solid hardwood console for amps
Powerline conditioning: 1 x GigaWatt PF2 on amps, 1 x GigaWatt PC-3 SE Evo on front-end components
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review Component Retail: €5.500, €850 for optional phono module


Though their kit was wildly popular already in Asia and particularly so in Japan, established German valve electronics house Octave enjoyed no distribution in the Americas for the longest time. When Dynaudio USA finally signed the brand a few years ago, the subtext was crystal. Here were modern tube amps that ate burly low-impedance Dynaudio speakers for breakfast. Unless your mental furniture was in storage, you'd predict from that not single-ended single-digit power but full-on pentode glory. Out 300B, 845 & Co., in 6550, KT120 and their sort. Yes. What you couldn't know? Octave's boss Andreas Hofmann designs as equal-opportunity engineer. He runs transistors and tubes where each work best. His €3.850 HP300MkII preamp for example follows its low-signal valves with a 'super-gain' semiconductor buffer. That isolates the critical tubes from the outside world with a constant load whilst achieving spectacularly low 22/56Ω output impedance on XLR and RCA respectively. 1Hz-1.5MHz bandwidth at -3dB for the same entry-level machine gives us another clue.


Just because they champion tubes doesn't mean Octave deal in repackaged antique circuits. They're firmly in the 21st century. Hence the second-from-the-top €7.100 HP500SE preamp model with its Siemens D3A/EF184 pentodes does the HP300MkII one better to generate an amazing 0.2Hz-2.3MHz bandwidth at -6dB. Company motto also insists on comprehensive protection and power management circuitry. With their amps and integrateds that includes a green eco mode and of course idiot-proof LED-set fixed bias for higher output power and greater accuracy. For more background, refer to our archives and seven prior Octave reviews.

The new HP300SE preamp is a refinement over the existing 300MkII which remains in the catalogue. Over the MkII the Special Edition adds connectivity, beefs up the power supply and relocates it to a separate chassis. It then improves the output stage which can drive 5-10m cable without performance degradation. Finally it sports 150Ω Z-out on transformer-coupled XLR and an Olympian gold-medal low 50Ω on RCA. Bandwidth again is an impressively wide 10H-200kHz at -1.5dB. Gain is super flexible across three stages of 12dB, 19dB and 25dB. MM/MC phono is optional, tube orientation a military sideways to suit the low-rider profile. Restating the strategic theme of valves plus semiconductors, Octave shuns tube rectifiers and tube regulators. Their power supplies thus go transistor all the way. With two out of the three core requirements for modern valve preamps aced—low output impedance and wide bandwidth—how does the HP300SE handle the third requirement of superior S/N ratio? With -108dB in low-gain mode. Shazam.


The business end has 3:2 RCA:XLR inputs, 1 fixed buffered output for perhaps a headphone amp, 2:1 RCA/XLR outputs, a ground-lift switch for the XLR output, a ground post for the optional phono board (which otherwise is a standard line-level input) and a 7-pin socket for the power umbilical. One RCA or XLR input can be configured as HT bypass. Gain level selection is on the front. The power mains is on top and at the very front of the power supply which only comes in black.


The tube complement for the reviewed line-stage version consists of one each ECC81/12AT7 and ECC88/6DJ8/6922. Because Octave does their own very stringent tube testing—they also design and wind all their own transformers—it is strongly recommended not to break...er, roll glass to maintain the machine's exceptionally low noise and high bandwidth.

To learn further specifics required chatting with Andreas Hofmann.