T+A V10 User Manual - page 30
BIAS / Operating hours display
As with all valve amplifiers, it is very important to set the
correct idle current (BIAS) of the output valves if the
amplifier is to provide optimum sound quality.
The V10 is equipped with a system which measures and
displays the BIAS value. This means that the parameter
can easily be checked from time to time without requiring
special measuring equipment.
The screen can also display the elapsed operating time
of the valves. It is a natural characteristic of these
components that they deteriorate gradually with age, and
for this reason we recommend that they be checked after
about 3500 hours of operation. They should then be
replaced if necessary.
Operating hours display
A brief press on the INFO button on the amplifier’s front
panel interrupts normal reproduction and displays the
operating hours of the installed valve set in the form of an
LED bar display on the screen.
Each of the LEDs 1 … 5 stands for 700 hours’ operation.
With a new valve set all five LEDs will glow; this indicates
that a further 3500 hours (5 x 700 hours) of operating
time are available until the next check. As the amplifier’s
operating time increases, the LEDs will extinguish in
sequence, in each case after 700 hours’ operation. When
all LEDs are out, we recommend that you have the
valves checked. When this time comes, please contact
your specialist
B dealer for advice.
Note:
The check is not absolutely essential; its only purpose
is to ensure that you continue to obtain the best
possible sound quality from your V10.
BIAS display
Pressing the INFO button again moves on to the display
of the BIAS value of the right-hand amplifier channel.
Press the INFO button again, and the BIAS value of the
left-hand channel appears on the screen.
The fourth time you press the INFO button the operating
hours / BIAS display disappears, and the V10 reverts to
normal play mode.
glowing
LED
1
1
1
1
Bias too low; adjustment recommended
2
2
2
2
BIAS at the lower limit (still no adjustment
recommended)
3
3
3
3
Optimum BIAS setting
4
4
4
4
BIAS at the upper limit (still no adjustment
recommended)
5
5
5
5
BIAS too high; adjustment recommended
Protective circuit
The V10 is fitted with a micro-processor controlled
protective circuit which constantly monitors all sections of
the amplifier during its entire period of operation.
The protective circuit ensures that the valves are heated
gently, thereby extending the useful life of these
components.
The protective circuit also prevents a load being placed
on the valves prematurely; this could damage the
components and lead to a loss of performance.
The monitor circuit measures the amplifier’s temperature
constantly, and adjusts the speed of the cooling fan to
the appropriate level in order to avoid overheating.
If the amplifier is overloaded, the monitor circuit switches
off the loudspeaker outputs. The flashing indicator on the
screen flashes constantly if the amplifier is switched off
due to an overload condition. If this should happen,
reduce the volume and wait until the unit switches itself
on again.
In the course of time the working point of the valves may
shift out of the optimum range, and if this occurs the
micro-processor switches on the warning symbol on the
screen to indicate that adjustment is advisable in order to
maintain the amplifier’s optimum sound quality.
Since valves have a natural ageing tendency, the
processor keeps track of the elapsed operating time of
these components. After 3500 hours of operation we
recommend that you ask your specialist
B dealer to
check the valves. When the stated operating time has
elapsed the processor lights the warning symbol on the
screen to alert you.
Since overloading causes the valves to age more rapidly,
the processor also takes this into account in calculating
the residual operating time.
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