Octave HP 300 SE Preamplifier

The HP 300 SE preamplifier is a further development of the legendary HP 300 MK2.

The HP 300 SE preamplifier is a further development of the legendary HP 300 MK2. It expands the Octave preamplifier range primarily through the large variety of connections. The HP 300 SE also offers outstanding sound quality thanks to improvements in the power supply and the output stage of the line amplifier. The newly developed line stage has an extremely high signal-to-noise ratio.


The OCTAVE HP 300 SE is a further development of the HP 300 MK2, whose ancestor HP 300 in turn benefited from the technical development of the reference Jubilee Preamp. The HP 300 SE goes beyond the HP300 MK2 in many ways. The most important are an external power supply with significantly advanced power supply technology, improved amplifier circuitry, amplification in 3 gain stages, XLR out with transformers and improved housing optics. The further development of the HP 300 into the HP 300 SE closes the gap to high-priced precursors. The sophisticated technology and the use of specialized output transformers in the XLR output make it an audiophile treat.

The power supply of the HP 300 SE consists of the external mains transformer with optimized mains filter characteristics and precise, extremely low-noise voltage regulators in the preamplifier. Both systems are perfectly coordinated and audibly reduce the noise and interference levels of the HP 300 SE. The balanced output is constructed with a precision balancing transformer. This transformer makes it possible to switch the ground connection to the power amplifiers on or off. This feature is helpful to prevent leakage current from the ground connection of the connected devices. Noise is caused not only by the specific properties of the tubes, but also by impurities in the network or interference within the power supply. In principle, these mains leakage currents are always present and have a negative influence on the sound. This is history with the HP 300 SE.

The OCTAVE HP 300 SE is a real all-rounder. It has two independent XLR inputs, three RCA inputs, a monitor output, two RCA outputs and one XLR output. The equipment is rounded off by a monitor output, which can be used for a headphone amplifier or any recording device, or the A/D input of a PC. The HP 300 SE optionally offers a phono MC input with a variety of setting options.

The gain can be selected in three levels, which allows the overall gain to be optimally adjusted to the efficiency of the speakers. Both outputs, XLR and RCA, have a very low output resistance. This means that cable lengths of up to 10m to the power amplifier have no negative influence. A helpful feature in modern systems is the multi-channel bypass (home theater function). The HP 300 SE also offers the option of selecting the bypass function for an RCA or XLR input.

Of course, the HP 300 SE has power management with soft start electronics, gain selector, monitor/record output and the HT bypass.


Phono MM oder MC

A phono MM or MC board can optionally be used in the V 70 SE, V 70 Class A, V 80 SE, V 110 SE and HP 300 SE. This additional board is internally connected to the phono input, which is then no longer available as a high level input.



  • Basic model: HP 300 SE Line
  • Options: Phono MC or MM
  • Design: Silver or Black
  • Tube complement: Line: ECC81, ECC88; Phono: ECC81
  • Inputs: 3 x RCA (one is phono with the option phono otherwise it is a line level input) / 2 x XLR
  • Outputs: 2 x RCA, 1 x XLR, 1 x Monitor (RCA)
  • Dimensions Preamp / Power Supply: 438 x 78 x 390 mm / 110 x 77 x 277 mm (W x H x D)
  • Weight Preamp / Power Supply: 9.0 kg / 3.0 kg
  • External power supply
  • Protection system: Protection circuit for device and tubes
  • Amplification selectable in 3 levels: Adaptation to the efficiency of the speaker
  • HT Bypass: Bypass mode for multi-channel receiver / TV
  • Gain factor: High: 25 dB = 18.5 / Med: 19 dB = 8.8 / Low: 12 dB = 4
  • Frequency Response: High: 10 Hz - 200 kHz -0.1 dB; Med: 10 Hz - 200 kHz -0.25 dB; Low: 10 Hz - 200 kHz -1,5 dB
  • Total harmonic distortion Low | Med | High: 0.005% | 0.007% | 0.03% at 3V / 7.5 kOhm
  • Signal-to-noise ratio: High: -92 dB; Med: -100 dB; Low: -108 dB


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