HP 300 MK2
3
INTRODUCTION
Congratulations and thank you for choosing the OCTAVE
HP 300 MK2
You are about to enjoy the benefits of one of the world's most innovative and
reliable preamplifiers. Take care of it, and your preamplifier 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
5
CONTENTS
Page
Introduction
1. OCTAVE technology ................................................................... 3
1.1. Differences to other tube amps ................................................... 3
1.2. Discription..................................................................................... 4
2. Safety instructions........................................................................ 5
2.1. Before you begin .......................................................................... 5
2.2. Placement..................................................................................... 6
2.3. Warranty....................................................................................... 6
3. Setting up ..................................................................................... 7
3.1. Connecting the amplifier............................................................... 7
3.2. Running in .................................................................................... 7
4. Operation: Front panel ................................................................ 8
5. Connections: Rear panel ............................................................. 10
6. Advanced function: The bypass mode......................................... 11
6.1. The HP 300 MK2 in the bypass mode.......................................... 12
6.2. The HP 300 MK2 in the two channel mode.................................. 13
7. Advanced function: Connecting a processor................................ 14
8. Programmable remote control...................................................... 14
9. Tubes............................................................................................ 15
9.1. Tube layout .................................................................................. 15
9.2. Replacing tubes............................................................................ 16
9.3. Tube service life ........................................................................... 16
10. Option: Phono MM/MC................................................................. 17
10.1. The role of the phono preamplifier ............................................... 17
10.2. The phono section of the HP 300 MK2 ........................................ 17
10.3. Guidelines for connecting to the phono section........................... 17
10.4. Adjusting the MC input................................................................. 18
11. Troubleshooting............................................................................ 20
12. Technical data and dimensions.................................................... 21
13. Specification................................................................................. 22
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1. OCTAVE TECHNOLOGY
1.1. Differences to other tube amplifiers
1. The design goal of OCTAVE amplifiers is honest, natural sound
reproduction. The sound characteristics of an amplifier are derived from
the sum of all its parts. Tubes do not themselves guarantee high qualit
y
sound.
2. The limitations of classic tube designs are evident as soon as you connec
t
the amplifiers. These designs often only perform to their full potential when
they are used with special cables and amps. OCTAVE amplification and
power supply technology has largely overcome these well-known
problems. Thanks to their unique output stage design, they will maintain
their optimum sound quality with virtually any amplifier, irrespective of the
cables.
3. OCTAVE employs the latest electronic circuit designs to create the bes
t
possible operating conditions for the tubes, and thus for the amplifier itself.
OCTAVE Tub e Tech nol og y
Power-
Management
Power supply
and
other functions
Amplifier +
Sound Quality
OCTAVE amplifiers are equipped with a proprietary control and monitoring
system we call Power Management. This is an "electronic brain" within the
amp that regulates and controls all of the amplifier's functions. It includes
the Soft Start Electronics that gently ramp up the heating and suppl
y
voltages to save wear and tear on the components. In the event of a
problem, the Power Management's protection system will disconnect the
unit from the power supply. Power Management helps us to achieve a
completely consistent sound while at the same time ensuring the total
reliability of our products.
4. OCTAVE amplifiers are hand built and individually tested. They are
designed and developed by Andreas Hofmann. The company has its own
winding department, in which all transformers are specially custom wound
for each amplifier.
5. OCTAVE amplifiers are 100% built in Germany. Our employees are highl
y
qualified and committed. We collaborate closely with local specialis
t
subcontracting companies. The hardware components are all
manufactured on modern CNC machines.
Sound
Amplifier
Design
Control +
Monitoring
Hand built
made in
Germany
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1. OCTAVE TECHNOLOGY
1.2. Description HP 300 MK2 MKII
The HP 300 MK2 MKII is a member of a new generation of tube preamplifiers built by
OCTAVE. The first model of this line was the reference preamplifier Jubilee. Heart of this line
is a newly developed circuit design, which still has the tube as the central amplifying
component, but the necessary output power is generated by a new type of super-gain
semiconductor circuit.
As OCTACE decouples the output load from the tubes, the HP 300 MK2 convinces with
excellent measuring results. Free from the output load the tubes can develop their tonal and
dynamic sound characteristics unrestrained. It sounds vivid, relaxed, totally free or with one
single word – simply light.
Because of that, the HP 300 MK2 preamplifier can be used extremely universal.
Furthermore, the HP 300 MK2 is manufactured perfectly, which also finds expression in the
stable, low resonance solid-metal chassis. Resonances are thereby ruled out. The solid
connecting sockets allow the connection of high-quality NF-wires with large plugs.
Every product of OCTAVE is built in German y in single-piece production and is subject to a
100% check. A 48-hour endurance run completes the final inspection.
Over and above that the HP 300 MK2 uses a lavish special power supply, which was
developed especially for the HP 300 MK2.
The power supply of the HP 300 MK2 carries out complex functions: On the one hand it
ensures a constant acoustic quality by preventing mains disturbances and by creating constant
working conditions with electronic voltage stabilizations. On the other hand the built-in control
logic guarantees highest reliability and achieves with soft-start-techniques the theoretically
maximal possible lifetime of the tubes (up to approximately 10 Years or more).
An additional function of the power supply is the protection circuit, which releases the output of
the HP 300 MK2 by a relay with a time delay or disconnects it immediately in case of a
malfunction. Click-interferences etc. caused by the power supply are therefore absolutely ruled
out.
Transformers are individually designed and produced in our own house.
The bypass / multi channel facility makes the HP 300 MK2 to one of the most versatile
preamps in this range. This technology is possible throughout a logic controlled input section.
The switching elements are high quality industrial grade gold contact relays.
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2. SAFETY INSTRUCTIONS
2.1. Before you begin
Before using your HP 300 MK2, please check your local line voltage and pay attention to this
manual
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 2 device (without an earth conductor).
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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. Cover
Never operate the amplifier without the cover.
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. 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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3. SETTING UP
3.1. Connecting the amplifier
1. In your own interest, please observe the safety precautions and positioning advice
(Chapter 2)
2. Before connecting your OCTAVE amplifier up, switch off all the other equipment that you
intend to connect to it. This will avoid a source of possible problems when you plug these
components in.
3. Connect the inputs from your amplifier to the appropriate outputs on the HP 300 MK2 amplifier.
4. Connect your loudspeakers to your power amplifier, making sure that you observe the correct
polarity (positive on the amplifier to positive on the speakers).
5. Check that the amplifier is switched off before connecting the power cable to the wall socket.
6. The stand by/power switch for the HP 300 MK2 is located on the front panel (see Chapter 4,
Operation)
7. Check that the volume control is not set at maximum before playing music through the
amplifier and the function switch
.is in the top position : Operate
8. Switch on the mains power, the push-button-switch is located on the front panel
of the preamplifier.
The preamplifier needs approx. 2 - 4 minutes warm up time. In the warm up
time the output is shorted to ground to avoid disturbances.
When switching the mode switch from normal to - 6 dB gain operation, the
output is muted for approx 2 minutes.
If you switch from high to low or vice versa the muting time will start again
9. Switch on the other components.
3.2. Running in
All OCTAVE equipment is subject to a 48-hour soak test at the factory to burn in the tubes. The
tubes are preselected for use in each particular model.
The sound quality of tube equipment improves throughout the initial running-in period of up
to three months.
During this time, daily use is beneficial (even at high levels) but not a requirement. Continuous
operation does very little to help reduce the running-in time and is therefore not
recommended.
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