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6. ADVANCED FUNCTIONS
No high voltages are switched and there are no high voltages near the switches.
The switchover is therefore not critical. If a power amplifier is running, while you are
switching the damping factor, the amplifier will go into protection mode. You then
have to switch off the device to reset the protection electronics.
When can it make sense to switch from DF L to H and why?
Normal dynamic loudspeakers do not represent a constant load for the power amplifier. The re-
sistance of a loudspeaker usually increases with increasing frequency. This behavior applies to
bass, midrange and tweeter speakers. Especially in the midrange, this effect leads to a higher re-
sistance of the speaker in relation to the bass. A power amplifier with a low damping factor will then
reproduce this frequency range a little louder. Switching to DF H can help here, as the “volume dif-
ference” then becomes smaller and the sound becomes more homogeneous.
The impedance curve of a loudspeaker is rarely published in the technical data; test reports from
the relevant press can help here.
Exceptions to which this effect does not apply are magnetostats and electrostatic loudspeakers.
Otherwise, in principle all dynamic two-way and multi-way loudspeakers are affected. However,
there are manufacturers who have implemented internal measures in their loudspeaker models that
largely prevent this increase in impedance. There is then an impedance linearization. In this case
the switchover is of minor importance.
6.7 Electronic Balanced Input Circuit XLR
As standard the Balanced Input is equipped with a precision low noise electronic balanced input
receiver. The Gain of this converter is 0 dB, which means that in case of the usual +6 dB of the
balanced signal of an electronic balanced preamplifier you will have a slightly higher Output level in
respect to the RCA connection.
In Position RCA 2 the Balanced Input Converter is switched into the single ended Mode and is
connected to the RCA Input. This is helpful in cases you have only a balanced signal connection to
the preamp.
Driving the MRE 220 SE via RCA with a preamplifier’ s Output Impedance of more than 500 ohms
the sound of the MRE 220 SE can degrade.
6.8 Ground Lift
The ground lift allows switching the ground connection of the MRE 220 SE to the preamplifier
between zero and a higher impedance.
Is the standard input equipped the ground resistance in the position “connected” is 0 ohms and in
the position “disconnected” it is 18 ohms.
In most cases you should choose the position “connected”, independent from using XLR or RCA.
Only in cases of problematic Ground-Earth situations with a noticeable hum you can use the position
“disconnect”.
Summary of Contents for MRE 220 SE
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