21
DISTRIBUTION AMPLIFIER/ZONE MIXER/MIC SPLITTER DA-410.
As seen in the main board component overlay, the jumper goes placed beside an indication.
It is important notice to install the jumper in the appropriate location, because placing it in the
wrong location could cause a short circuit in the power supply or additional malfunctions in the
unit.
EQUALIZER CARD CONFIGURATION
The next picture shows the component overlay of an equaliser card. As seen in the
picture, there are 6 resistors called RG+, RG-, RQ, RQ,' RF and RF'. This resistors define the gain
(RG+ or RG-), the bandwidth (RQ and RQ') and the centre frequency (RF and RF') of the
equalisation point:
Before adjusting an equaliser card, you should decide the gain, bandwidth and centre
frequency that you want to implement. Good results are obtained when using an external
parametric equaliser inserted in the signal path and the results are verified with a spectrum
analyser. Then, translate the obtained parameters to the next tables. A theoretical
approximation can also be used from the loudspeaker manufacturer graphs.
GAIN CALCULATION
There are two resistors in the equaliser card, labelled RG+ and RG- that configure the
equalisation point gain. For the gain you should only place a resistor, if you want positive
gains should place it in RG+, and if you want gains negatives (attenuation) should place it in
RG-.
The maximum gain of the equalisation point is 15 dB, since this resistor could not be
less than 2K
Ω
. If you want unitary gain, doesn't place any resistance.
The next table shows the resistors that you should use for gains between 1 and 15 dB,
in 1 dB steps. If you want an intermediate gain you are able to calculate an intermediate
value:
GAIN
5% RESISTORS
1% RESISTORS
1 dB
82 K
Ω
82,5 K
Ω
2 dB
39 K
Ω
38,3 K
Ω
3 dB
24 K
Ω
24,3 K
Ω
4 dB
18 K
Ω
16,9 K
Ω
5 dB
13 K
Ω
13 K
Ω
6 dB
10 K
Ω
10 K
Ω
7 dB
8,2 K
Ω
8,06 K
Ω
8 dB
6,8 K
Ω
6,65 K
Ω
9 dB
5,6 K
Ω
5,62 K
Ω
