Octave V 16 Single Ended, Owner'S Manual

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11. TROUBLESHOOTING
Driver tube heater fault
When a driver tube heater fault occurs, you will normally lose an entire channel (depending on which
driver tube system is affected by the faulty heater). This can only be established by a visual
examination. The heater filaments are often difficult to see inside the driver tubes, since they only
protrude very slightly from the tube system. OCTAVE uses double triodes, the Input tube V 4 for
example, i.e. there are always two identical tube systems within the glass envelope. Because each
of these triode systems has its own heater, you should always be able to see two glowing filaments.
If you can only see one, it means that the tube is faulty. The other two driver tubes of the V 16 are
single tubes with only one filament glowing.
 A tube has developed an air leak
The glass envelope of all tubes normally contains a vacuum. In order to maintain the vacuum
throughout the service life of the tube, there is a device inside the tube that absorbs the residual gas.
It is called the getter pill. It normally takes the form of a small crucible near the top of the tube. It
contains a substance known as the getter, which absorbs and permanently retains the residual gas.
This device ensures that the tube maintains a high vacuum during its entire service life. Hairline
cracks around the base and leaks around the socket pins can cause the tube to take in air. Because
the getter is only able to absorb a finite amount of gas, it will soon stop working. The silver coating
at the top of the tube will then begin to discolor. As soon as a certain amount of air leaks into the
tube, it will stop working completely and the heater filament will burn through.
Tube faults that trip the protection system
The protection system continuously measures the current flowing into the two power tubes.
Depending on the problem, this current may exceed a specified limit and cause the protection system
to switch the power stage off. The red protection LED will light up to show that this has happened.
Once the protection circuit has been tripped, your amplifier will not produce any output. Exceeding
the specified current limit can have a variety of causes.
 Faulty output tube
Aging and mechanical stresses from rough handling during transport can create an unwanted
connection inside the tube, which can lead to failure of the tube.
How can you recognize a faulty tube? If you do not know what fault caused your amplifier to cut
out, it is a good idea to disconnect the speakers and switch the V 16 Single Ended off and on again.
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You can switch ON the V 16 Single Ended with only one Output Power tube to check which tube
is faulty.
 Faulty driver tube
In very rare cases, a problem with one of the driver tubes can cause the V 16 Single Ended to switch
off. If one of these tubes is indeed responsible for the problem, output tubes in the affected channel
will behave erratically.
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you can turn ON the V 16 Single Ended without the driver tubes to check if one of the driver
tubes is responsible for the issue.
 Tube faults that degrade the sound
These faults are relatively uncommon and usually a result of a fault already described above. Thanks
to the controlled soft-start circuitry, the tubes will retain their tone throughout their working life. The
V 16 Single Ended's sophisticated, low-noise power supply circuits push hum and noise down to
negligible levels. Tubes do not inherently produce hum or hiss: these problems are simply side effects
of older, classic tube technology.
Noise, crackling or similar undesirable noises can be caused by residual gas or other residues in the
tubes. This kind of noise does not often reach a level that could be considered annoying, although
the nearer to the "front" the particular tube is, the more it will tend to make itself felt. In the V 16
Single Ended, this would be tube V 4. As it is rare for both systems in a double triode to be equally
affected, the noise levels in each stereo channel will be different.