AUDIO FUTURA
AUDIO FUTURA
AUDIO FUTURA
AUDIO FUTURA
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Bellini preamplifier – Virtual Battery off line power supply
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During the switching time the voltage at the input of Voltage regulator 1 and 2 is
supplied by the capacitor C1 and C2.
Of course the story goes on cycle by cycle setting the appropriate voltage at the input
of Voltage regulators 3 and 4.
Fig. 1 - Schematic
The virtual battery works supplying all the preamplifiers circuits separately from the
50Hz/60Hz area, eliminating in such way the 50Hz/60Hz interference. The high
frequency interferences are stopped by the AC filter and also reduced by the virtual
battery.
In the measurements beyond we can see the noise spectrum measured at the RCA
output of the Bellini Virtual Battery Preamplifier with no signal applied and input 2
selected. The scale of the frequency axis is logarithmic to evidence the low
frequencies range.
FFT Spectrum Analysis at Volume 0
