8. Configuration
8.1 Balanced and unbalanced Inputs
8.2 Input Gain Controls
8.3 Audio Limiters
The amplifier can accept unbalanced and balanced lines. For optimal performance and with
longer cable runs, use balanced lines whenever possible. The driving device should be equipped
with a balanced output. With short cables inside one rack the issue is not that critical.
A balanced connection provides excellent noise immunity from interference and ground loops.
A balanced audio connection is accomplished by using a differential pair of signals, isolated
from ground. While these connections provide great noise immunity, care must be taken when
connecting balanced and unbalanced equipment together.
The amplifier is equipped with rear gain control for each channel. The gain range of the control
is from – infinite to +6 dB (0 dB in middle position). Full gain of the amplifier is reached with a
balanced input signal of 1.85 Vrms (with gain setting at 0 dB). In bridge mode only 1 input gain
(nr. 1, 3, 5 and/or 7) is operating.
To reduce severe clipping, which can result in overloading of an amplifier channel, each channel
is equipped with a soft-limiter. The limiter circuit senses the output signal and when it starts
to reach its maximum output level the input signal is reduced accordingly. If one continues to
run the amp with high input signal beyond the limiters capabilities, the amplifier channel(s)
will start clipping again, distortion will increase rapidly and the overload protection circuit will
be triggered (channel(s) will turn off for a moment)! To avoid this: reduce the input signal until
clipping indicators do not light up anymore. The limiters are factory activated and can be turned
off by removing an internal jumper (1 per channel), see picture below. When a channel pair is
running in bridge mode, for example Ch.1 & Ch.2, only the limiter for Ch.1 is operating (Lim.3 for
Ch3/4, Lim.5 for Ch5/6 and Lim.7 for Ch7/8).
NOTE: To change the limiter setting, make sure the amplifier is disconnected from any AC-mains
and DC-battery connection before opening the unit!
4
8 3
7
6
2
1
5
8. Configuration
Jumpers on rear
vertical board
(remove to
de-activate):
1. Limiter channel 1
2. Limiter channel 2
3. Limiter channel 3
4. Limiter channel 4
5. Limiter channel 5
6. Limiter channel 6
7. Limiter channel 7
8. Limiter channel 8
9