Owner`s manual

Viola Laboratories Spirito Reference Series Preamplifier Owner's manual
8
Special Design Features
Congratulations on your purchase of a SPIRITO Reference Preamplifier
by Viola Audio Labs. While your new preamplifier is straightforward in
everyday use, it includes several design features that are responsible for its
outstanding performance.
The Spirito preamplifier is a two box set, a stereo preamplifier with
separate power supply. The separate power supply assures complete
freedom from electro-magnetic interference (EMI) produced by the
electromagnetic power supply components, i.e. the power transformer and
inductor (or choke).
The inductor (choke) input filter power supply design was chosen because
it produces far less EMI than conventional capacitor input systems. The
inductor (choke) input filter system greatly reduces the electrical stress
placed on the power supply components. Therefore, this greatly increases
the life span and reliability of the power supply components. Capacitor
lifespan in particular can be increased by at least an order of magnitude.
The virtual elimination of the high peak ripple currents also minimizes
intermodulation distortion on the power supply “rails” and ground returns.
Additional power factor (PF) correction circuitry increases the PF from .9
(typical for “choke” input supplies) to .96 (a power factor of 1 [unity] is
considered ideal).
The power supply utilizes large, conventional components instead of a
switching power supply because they can operate at power levels several
times their continuous power ratings for longer periods. Given the duty
cycles found in even the most demanding music, large conventional
magnetic components can be used in audio preamplifiers whose
continuous sine wave power ratings would otherwise require a switching
power supply rated at 3 times that of the conventional type.
The conventional magnetic supply used for this preamplifier does not
utilize high frequency switching and therefore is devoid of any high
frequency noise. It offers much higher reliability and does not have to be
derated nearly as much as an equivalent switching power supply for a
given ambient temperature.
1.4 Balanced design
A truly balanced input topology eliminates the need for an input buffer
amplification stage and allows the first stage differential amplifier to be
driven directly by the source. Matched impedances are presented to the
source and both signals travel through identical circuit paths. A balanced
input signal remains balanced throughout the voltage gain stages.