TWITTERING MACHINES Review｜OCTAVE V 70 Class A Integrated Amplifier

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Date: 2024-11-12

The Octave Audio V 70 is a Class A push-pull pentode integrated amplifier capable of outputing a specified 50 Watts of power into 4 Ohms.

If you read my review of the lovely Octave V 16 Single Ended Integrated/Headphone Amplifier, you know a bit about Octave’s history and how the company’s roots go back to 1968 when Karl Heinz Hofmann founded the transformer winding factory Hofmann in Karlsbad, Germany. His son, Andreas Hofmann took over the Hofmann company from his father in 2000, gave it its new name—OCTAVE Audio—and a focus on the tube-based electronics he’d been designing and building since the 1970s. History is something to respect, imo.

The Octave Audio V 70 Class A Integrated Amplifier incorporates the company’s Dynamic Bias Control and I’ll let them do the talking:

Dynamic Bias Control means that Andreas Hofmann has found ways to dynamically shift the limited dynamic range, and thus the limited power of the Class A concept, according to the requirements. The development of the dynamic operating point setting enabled a self-regulating Class A amplifier with approximately twice the output power of 50 W RMS with up to 70 W (with Super Black Box) peak power.

This technology combines the tonal purity of Class A with the dynamics and performance of push-pull A / B technology.

The modern concept of a Class-A push-pull amplifier in a pentode circuit makes it possible to guarantee the Class-A virtues over the entire frequency response up to maximum modulation. The enormous power, with up to 70 watts peak power, is significantly above the performance level of conventional Class A amplifiers and is more than sufficient for most speakers.

It just so happens I also have Octave’s Super Black Box in for review, so we’ll see what kind of more, beyond power, that brings to the table.

The V 70 comes with a total of 5 line level inputs (3x RCA, 1x XLR, 1x Front Channel/HT Bypass), a Tape In and Pre Out. A MC or MM Phono module are optional. There’s also a single set of speaker binding posts, a Black Box Connector for adding one of Octave external power supplies, a 3-position Ecomode toggle switch (“Ecomode serves to reduce heat and unnecessary power consumption when the unit is switched on but not in use”), and an IEC inlet. I’ll let Octave explain the reason for the Power Selector High/Low switch:

Power High and Low, so that the device can be optimally adapted to different power tubes. Due to the high power in Class A operation, a KT 120 or KT 150 tube must be used for Power High. Less powerful KT88 or 6550 types should be operated at Power Low. Around 15 W Class A and 25 W music power are still available.

The V 70 also ships with a quad of Tung Sol KT120s but you can also use 6550s, KT90s, KT100s, KT120s, and KT150s in their stead. The preamp stage employs a single 12AX7/ECC83 and a pair of 12AT7/ECC81s. The front panel’s two dials dial in input selection (left) which also has a stop for checking the auto-bias of the output tubes while the other dial is for volume control. In between sits a display that shows the selected input, Bias status when in Bias mode, and amp status (Power, Soft Start, Protection, Front Channel).

There’s an included chunk of aluminum remote with but two buttons—good and better. The amp and remote’s matte aluminum finish is a favorite of mine for two reasons—I like the way it captures light and you can touch either without leaving finger smudges. To my mind it makes perfect sense to finish something that’s going to be touched with a touch-proof finish.

Specifications
Output Power: High: 2 x 50 W / 4 ohms; Low: 2 x 25 W / 4 ohms
Frequency response: 20 Hz – 70 kHz @ 50 W – 1 / – 3 dB
Total Harmonic Distortion: 0.1% at 10 W / 4 ohms
Signal-to-noise ratio: – 100 dB / 50 W unrated
Options: Phono MC or MM
Design: Silver or Black
Tube Configuration: 4 x KT 88-S4A-Carbon, optional 4 x KT 120 TS
Inputs : 5 x line level RCA (one is a bypass input and one is a phono input with the phono option) / 1 x XLR
Outputs: 1 x pre-out regulated / 1 x record output RCA / 1 x loudspeaker output
Dimensions: 451 x 150 x 415 mm (W x H x D)
Weight: 22.1 kg