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1.4 Input cards
The input circuits act extremely fast and use special semiconductors for exact and nearly noise free sound
reproduction.
Unused input cards do not only swich off the incoming signals but also the signal grounds. This technique
ensures that only the active source is connected to the PA8. This avoids ground loops and ensures a totally
hum free and optimally clear reproduction of the music signals.
The volume control is done by highly precise integrated circuits. They allow setting in 0,5 dB steps and their
channel balance is better than 0,05 dB. All this provides an absolutely precise, musical sound reproduction
from lowest to highest listening levels.
The input cards are connected to the backplane. They deliver fully balanced signals with constant high level
and low impedance. This makes the internal signal paths impervious to influences from the environment.
1.5 Output cards
The output cards receive the balanced high level signals from the selected input card. These signals are
directly fed to the electronic volume setting circuitry. The volume setting circuits also process the signals in
balanced technique. After volume and balance setting the signals are passed to the output stages.
The output stages are all made in class-A-technique. They offer low impedance and can easily deliver the
necessary current even for long cables with high capacitance.
1.5.1 Tube outputs
The PA8 can be equipped with up to two tube outputs. As well balanced XLR or RCA cinch. These outputs
use one double triode for each channel. The triodes are operated in balanced mode. The high voltage for the
tubes is supplied by a precision high voltage generator. The generator circuit works from a regulated DC
supply and thus fully independent of the varying mains voltage.
1.6 Special informations about the plug in cards
For more detailed informations please refer to the operating instructions which are delivered together with
the individual cards.
