The V 70 Class A is Octave’s newest integrated amp by designer Andreas Hofmann. Class A amplifiers are known for bewitching midrange in both push-pull and single-ended amplifiers due to their low distortion, but unfortunately this is commonly paired with low power, dynamics and excessive heating of the amplifier. It was therefore important to develop a concept that would bring the undisputed tonal advantages of this principle to life without the aforementioned shortcomings.
Dynamic Bias Control
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.
Auto-Bias Circuit
In the case of the V 70 Class A, an auto-bias circuit is used. The amplifier adjusts itself to the tube used and does not require any adjustment controls. The proven BIAS measurement with the colored LEDs is still available, however, only to check that the four output tubes are working properly.
Similar to the other top models from Octave, the V 70 Class A also has the power preselection, 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.
