The purpose of this module is to limit the start up current of large power amplifiers. A big
transformer has a low DC impedance on the primary side, and thus draws a huge start up current even
if no capacitor bank is connected. This can blow fuses of up to 10 Amperes easily. When a big capacitor bank is added,
this makes the start up problem even worse. Also the high charge currents will limit the operational life of the capacitors.
With this module mounted, the transformer and capacitor bank is started up slowly; power is limited
with a 330R power resistor with high pulse handling specifications. After 3 seconds a quality relay jumps the mains power directly to the transformer. | | Thus, after the slow start no circuitry except the high reliability relay contacts are in the power path - eliminating losses.
It has shown there is a positive effect on the sound quality, compared to adding the power directly.
Normally, it takes ½ to 1 hour from turning on the power until an amplifier sounds optimally. With a soft start
circuit this warm up time is reduced to a few minutes. Presumably because some of the negative effect on sound
quality, that is normally experienced on amplifiers without a soft start circuit comes from the huge
start-up current on the capacitors when cold starting the amplifier. This current can be in the reign of 70 - 200 Amperes.
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