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1. DESCRIPTION OF THE V 40 SE
The
Octave V 40 SE
is a push-pull pentode integrated amplifier with line stage preamp section and
2 x 40 W RMS output power (into 4 ohms loads). As with all Octave models, the all research and
development (R&D) and production has been conducted exclusively in-house, and the amplifiers is
comprehensively safeguarded against user error and parts wear – including catastrophic power tube
failure.
The V 40 SE improves upon the V 40 predecessor, with upgrades made in the amplification stages
as well as the power supply. The coupling capacitors of the power tubes, now 1.5 µF in the V 40 SE,
have been increased by a factor of three compared to the V 40, resulting in a lower frequency
response. Ultra-low leakage Tantalum electrolytic caps are now used instead of Aluminum
electrolytic caps in the driver circuit. The heater voltage of the driver tubes has been precisely
stabilized to reduce hum and noise that would otherwise be caused by the heater system. The heater
and the supply voltage are both controlled via the power management circuit. The stabilization of the
heater and power supply voltages ensures the stable, drift free operation in the mains range of +/-
15 %. Every output tube in the V 40 SE is protected against over-current. Also, both the protection
and the BIAS systems are protected against over-voltage caused by failed tubes.
BIAS Measurement
The output stage of the V 40 SE has an adjustable quiescent current (BIAS) control. The controllers
are accessible from the outside, the correct BIAS is set using precision controllers and a measuring
system with 0.3% accuracy. Each end tube is individually protected against overcurrent or overload.
If the permissible limit values are exceeded, the device is switched off electronically internally.
Option (Super) Black Box
The V 40 SE is fitted with a connector for the optional Octave
“Black Box”
capacitance modules –
available in normal and “Super” versions. The use of the Black Box or Super Black Box significantly
increases power supply capacitance to stabilize current delivery and reduce impedance interaction
of the load, thus improving dynamic range, separation, depth, soundstage size and articulation. This
enables optimizing the V 40 SE in respect to the speaker, which is a tremendous benefit if the
speaker is difficult to drive.
Input Section:
The input section of the V 40 SE features five line level single ended Inputs and two single ended
Outputs. One is a regular record output; the other Pre-Out is a regulated preamplifier output. This
output is buffered with an integrated circuit to reduce the negative influence of any connected unit
(normally an active subwoofer).
The Input labelled “Front Channel“ is coupled with a relay that bypasses the volume regulator. In the
“Front Channel” selector position the V 40 SE functions as a stereo amplifier. The bypass relay can
be disconnected internally if this function is not desirable.
The record Output is always active, and the record Output is shorted to ground in the “Front Channel”
position. Therefore it is not possible to record off of the “Front Channel” signal. The input section is
not built in the standard “Tape Monitor/Record” schematic, and thus there are less relay contacts in
the signal path and the effect is the same.
