AUDIO FUTURA spa
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. Its scale of the frequency axis is logarithmic to evidence the low frequencies range.
FFT Spectrum Analysis at Volume 0
Bellini preamplifier – Virtual Battery off line pow er supply | 4 / 5 |