Bridged loudspeaker connections
The EMA amplifi er can also be bridged for a mono confi gura-
tion. This allows the amplifi er to be used for one or several
subwoofers or mid-range drivers. In this confi guration, the
amplifi er combines the right and left channel to a single-
channel output (mono output).
Note:
The amplifi er can add the right and left signal information
only if the right as well as the left RCA connection were
carried out.
Caution:
In a bridge circuit, the amplifi er load must be 4 ohm or
higher. A lower load leads to an overheating or switch-off
of the amplifi er and can cause permanent damages.
Adjusting the type and range of the
frequency crossovers
With the EMA 255, the type of frequency crossover (i.e. "Low
Pass" or "Hi-Pass") and the desired entry frequency can be
adjusted. For example, if a pair of subwoofers is to be con-
nected, the low-pass settings shown are required (Fig. 3). The
entry frequency is dependent upon the frequency range of
the loudspeakers (see recommended frequency range of
the loudspeakers).
High-Pass
At a setting of 80 Hz, the amplifi er has a frequency range of
80 Hz to 30,000 Hz.
Low-pass frequency control
This control is active if the switch is in the position "Low-Pass",
and allows for setting the desired entry frequency.
Example:
At a setting of 150 Hz, the amplifi er has a frequency range
of 10 Hz to 150 Hz.
Bass boost
The bass boost control is used to adjust the bass response
of the amplifi er.
The setting options are: 0 dB / +6 dB / +12 dB.
Power-on indicator
(PWR / PRO)
Green LED:
Output stage on, regular operating status.
Red LED:
Output stage is electronically switched off due to an error.
Recycling and disposal
Please use the return and collection systems avail-
able to dispose of the product.
Subject to changes
EMA 255
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