Balanced Audio Technology VK-5 Owner's Manual - page 6
tubes in the unit warm, but well below their full operating temperatures. The filament
voltage in this mode is reduced to about one half of its nominal value. This allows the user to
keep the preamplifier warm for prolonged periods of time without sacrificing tube life.
While the VK-5 will sound superb right after turning it On, some owners may prefer to keep
it warm (in Sleep Mode) when not in use.
Gain Controls:
Separate left and right gain controls replace the traditional balance control and provide up to
4 dB attenuation for each channel. Turning them counterclockwise will reduce the gain of
the corresponding channel. The preferred position is up fully clockwise (pointer at 12
o'clock).
Power indicator LED:
The power indicator light on the VK-5 works as follows:
In On mode the LED glows at full brightness indicating normal operation.
In Sleep mode the LED brightness is reduced and is roughly proportional to the
filament temperatures of the tubes.
When turning the cold unit into Sleep mode for the first time, the tubes will require several
minutes before reaching their normal Sleep mode temperatures. Accordingly, the LED power
indicator will not turn On immediately, but will gradually become brighter as the tube
filaments warm up.
On the other hand, when switching the running unit from On into Sleep mode, the brightness
of the LED power indicator will not change immediately, since tube filaments will gradually
start cooling off. As they do, the indicator brightness will continue decaying until settling at
a steady state, indicating that the tubes have reached their proper Sleep mode temperatures.
This may require several minutes.
Going from the Sleep to the On state will produce an immediate increase in the LED power
indicator brightness, signaling full power operation.