V70
3
INTRODUCTION
Congratulations and thank you for choosing the OCTAVE
V 70
You are about to enjoy the benefits of one of the world's most innovative and reliable
amplifiers. Take care of it, and your amplifier will provide you with many years of
listening pleasure.
You often hear people claim that there has been no real progress in tube amplifier
design for years. The operating principles of tubes have been documented
extensively and are well known to amplifier designers. The same can, of course, be
said for transistor amplifiers.
Nevertheless, there is still room for further development with both of these
technologies. This is both necessary and desirable. With tube amplifiers in particular,
a general reluctance to depart from the classic circuit designs has not done the
technology any favours. Today's loudspeakers and source equipment provide better
performance than ever before, but also make greater demands on amplifiers. Modern
sound reproduction equipment delivers a level of performance at a price that simply
would not have been possible 20 or even 10 years ago.
These advances have been achieved through the application of cutting edge
technology as it becomes available and affordable.
Integrating these technologies into amplifier design demands a detailed knowledge of
the inner workings of amplifiers and an appreciation of the sonic ramifications of each
modification.
We have specialized in tube amplification for the past 20 years, during which time we
have developed a number of innovative technologies that have earned us a
reputation as one of the leaders in the field.
We hope you will enjoy many hours of wonderful music with your OCTAVE amplifier.
Andreas Hofmann
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CONTENTS
Page
Introduction ................................................................................................. 3
1. Description of the V70...................................................................... 7
2. Safety instructions............................................................................ 9
2.1. Before you begin.............................................................................. 9
2.2. Placement ........................................................................................ 10
2.3. Warranty........................................................................................... 10
3. Setting up......................................................................................... 11
3.1. Connecting the amplifier .................................................................. 11
3.2. Running in........................................................................................ 11
4. Operation: V70 front panel .............................................................. 12
5. The BIAS measurement system ...................................................... 14
6. Connections: V70 rear panel ........................................................... 15
7. Tubes
7.1. Removing the grille .......................................................................... 16
7.2. Tube layout....................................................................................... 16
7.3. Tube service life............................................................................... 17
7.4. Replacing tubes................................................................................ 17
8. Programmable remote control.......................................................... 18
9. Using the Black Box or Super Black Box ........................................ 19
9.1. Option: External Black Box .............................................................. 19
9.2. Option: External Super Black Box.................................................... 20
10. Troubleshooting................................................................................ 21
11. Technical data and dimensions........................................................ 22
12. Specification..................................................................................... 23
13. FAQ.................................................................................................. 24
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1. DESCRIPTION OF THE V70
The V 70 is an integrated amplifier with a push-pull pentode output
stage producing approx. 2 x 70 W at 2% THD.
LOAD STABILITY
Through optimization of the pentode design, we have developed a
power amplifier section with exceptional load stability. This load sta-
bility is important because the minimum impedance of modern, high
performance loudspeakers can be anywhere between 2.5 and 8
ohms. As impedances under 4 ohms are relatively common, we have
optimized our output transformers for 4 ohm loudspeakers. There is
no provision for 8 or 16 ohm outputs because:
1. There are practically no true 8 or 16 ohm loudspeakers being
made any more.
2. A properly optimized output transformer with additional tappings
would make the design very complex and would also add unnecessarily to the cost. It is not harmful to drive an 8 ohm loudspeaker from
a 4 ohm output. The amplifier simply delivers slightly less power into
an 8 ohm load.
ELECTRONIC
STABILIZATION
The really new feature of the V 70 is the electronic stabilization of the
preamp power supply .
Because of the high voltages involved, the technology is highly sophisticated. First used in the Jubilee monoblocs, this technology is
particularly beneficial to the sound quality of smaller amplifiers. Interaction of the power amplifier with the sensitive input stages is eliminated. The sound gains more silence, without any sense of edginess
- an effect normally only achieved with "giant" power supplies. Bass
reproduction also gains in authority.
POWER
MANAGEMENT
Preamplifier stabilization is integrated with the electronic soft start
surge control (power management).
Soft start - ramping up of the heating and supply voltage at turn-on is
extremely important for the life and the sound performance of the
tubes. It also relieves the power supply components of the strain of
handling huge surge currents at turn-on.
During start-up, the Wait LED lights up on the front panel. When it
goes out, the amplifier is ready for use. Soft start is also activated
whenever there are strong fluctuations in the supply voltage, such as
may occur during thunderstorms.
PROTECTION
SYSTEM
Many manufacturers fail to incorporate electronic or even passive
protection systems in their tube amps, which means that the life - and
indeed the operational safety - of these amplifiers is greatly dependent on factors over which the user has no control.
We refuse to leave safety and service life to chance.
OCTAVE fits its power amplifiers with an electronic protection system
as a matter of course.
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1. DESCRIPTION OF THE V70
Our protec tion system incorporates an independent circuit that monitors
the power output of the four power tubes. It switches the power supply
off when the maximum permissible values are exceeded. The red OFF
LED illuminates to show you when the protection has been activated.
This can happen for a number of reasons - for example, if the speaker
outputs are short circuited or if the power amplifier is overdriven. The
protection system protects the amplifier and the tubes from overload.
The V 70, like all Octave amplifiers, is thus fully protected against the
possibility of serious damage that often affects other valve amplifiers
when overdriven.
Our system - soft start and protection circuit - rules out any possibility of
'user error'.
Owners of tube amplifiers usually receive lots of advice like: Never operate without the speakers connected; Follow the switch-on sequence
exactly; Switch valve amplifiers on and off as little as possible, etc. This
is certainly important advice for many amplifier brands, but is not necessary with the V 70. The built-in control system automatically takes care
of this.
PROTECTION
SYSTEM
Another extremely useful feature is the bias (idle current) measuring
facility.
Unlike the simpler class-A power amplifier type, AB amplifiers require
adjustment of the negative grid bias to optimize idle current for the power tubes. The setting can change as the tubes age and it must also be
adjusted whenever tubes are replaced. Normally, this requires test equipment and a knowledge of what and where to measure.
Setting the bias used to be a job for an electronics technician, but with
the V 70, you can check and adjust the bias without any tools while the
amp is on.
This adjustment has a huge influence on the sound quality and performance characteristics of an amplifier (see diagram 1 under "Specification").
BIAS
All of these features make the V 70 a unique product in its class and a
true, state-of-the-art design. The V70 benefits from the know-how and
technologies that make our top of the range amplifiers, the Jubilee Line,
reference class products.
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2. SAFETY INSTRUCTIONS
2.1. Before you begin
Before using your V 70, please remove the protective grille and install the output tubes supplied
with your amplifier in the appropriate sockets (see Removing the Grille and Tube Layout). Replace
the grille before switching on.
Operating the amplifier without its protective grille is dangerous and not recommended.
In case of emergency: disconnect the plug from the mains supply
Never use an amplifier that is damaged or faulty. Make sure that it cannot be used until it has been
repaired by a qualified service engineer.
Make sure that there is easy access to the IEC socket and power cord.
Do not open the case
There are dangerously high voltages and hot tubes inside this equipment. To avoid a burn or the
risk of electric shock, never allow anyone except qualified personnel to open the case or remove
the grille.
Servicing and maintenance
For reasons of safety, please ensure that servicing, repairs and other modifications to OCTAVE
equipment are carried out only by a qualified technician. Fuses should also only be changed by a
qualified technician. Always replace fuses with ones of the same type and rating. If your amplifier
requires servicing, please ship or take your equipment directly to OCTAVE or to one of our authorized service centres.
Explanation of the warning symbols:
The exclamation point within an equilateral triangle is intended to alert the
user to important operating and maintenance instructions.
The lightning flash with arrowhead symbol within an equilateral triangle is
intended to alert the user to the presence of uninsulated 'dangerous voltages' within the product's enclosure that may be sufficient to constitute a
risk of electric shock to persons.
Before connecting
Make sure that the voltage of your amplifier matches your electricity supply voltage.
Grounding
This amplifier is a protection class 1 device (with an earth conductor). To exclude the risk of electric
shock in the event of a fault, the unit must be grounded. Use a three-core mains cable with a threepin plug (supplied).
Safety warning: hot tubes!
Warning: Remove the protective grille at your own risk. OCTAVE accepts no responsibility for injuries caused by the removal of this grille.
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2. SAFETY INSTRUCTIONS
2.2. Placement
1. Location
OCTAVE equipment is designed strictly for use in a dry domestic environment. Do not use it in the
open air or in damp environments!
Never place plants or liquid filled containers on your OCTAVE equipment. Take care that objects
do not fall or liquids are not spilled into the enclosure. Should this happen, remove the mains plug
immediately and have your amplifier checked by a qualified service technician.
Condensation may form if the amplifier is taken from a cold environment into a warm one. If you do
this, wait until the amplifier has reached room temperature and is dry before switching it on.
Avoid installing the unit close to sources of heat such as radiators or anywhere that it may be in
direct sunlight.
Do not operate the unit near flammable materials, gases or vapours. Avoid areas where there may
be heavy accumulations of dust or where the unit may be subject to mechanical vibration.
Place your OCTAVE amplifier on a stable, even surface.
2. Grille
Never operate the amplifier without the protective grille.
3. Ventilation
Make sure that your amplifier has a good flow of air around it. If you intend to install your equipment in a cupboard or a shelf unit, ensure that there is at least a ten centimetre gap between the
ventilation slots and the walls all around the amplifier. The rear panel of cupboards should have
ventilation holes to prevent heat build up. Do not rest the equipment on a soft surface such as carpet or foam sheeting.
2.3. Warranty
OCTAVE can only guarantee the safety, reliability and performance of this unit if modifications and
repairs are carried out by specialized personnel and if the amplifier is operated in accordance with
the instructions contained in this manual.
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