User Guide

5
Dear Audiophile,
Congratulations and thank you for choosing Maestro Line Preamplifier Special Edition. You’re now
the owner of a unit that establishes a new reference in the category of high-quality and high-versatility stereophonic
products. Maestro Line Preamplifier Special Edition provides circuital solutions with no
compromises and features capable to satisfy advanced users’ demands. We built our preamplifier with high-performance
circuits, separated circuit sections for each channel, function-based and channel-based circuit sections and PC/ house-
automation systems connection. Maestro Line Preamplifier Special Edition solutions make the unit
a valuable and durable investment
Features
Double-chassis to separate the line section from the digital and power supply section.
Analog supply: VR Power Supply (voltage reference): The power supply we have designed develops a philosophy
different from that generally followed in the audio field. In fact, the power supply is normally obtained from a secondary
stage of the transformer whose voltage is rectified and then stabilized and filtered as much as possible in order to reduce
the ripple. In the Maestro Line Preamplifier SE a “traditional” power supply, such as the one previously described, has
been implemented to have a very clean voltage (as much as 3 different stabilization stages have been used for each
supply!) but the voltage is not used to supply the preamplifier section! Instead, the voltage, which is already very clean,
just supplies the circuit where the proper voltage for the preamplifier circuits is generated. The voltage to supply the
preamplifier section is derived from an extremely clean and stable (both thermically and temporally) voltage reference.
Such voltage is hence treated to reach the level required for the preamplifier section. All the chain has been designed
using extremely low noise strategies. The board for example is a 4 layer one (to have a generalized bypassing of every
signal) as apposed to the standard 2 layer boards commonly used in the audio field…
Pre section: the preamplifier section has been revisited changing the passive components after a series of highly
accurate listening tests. In the course of such tests many different kinds of passive components have been checked in
several different positions to obtain the best sound coherence. Moreover, in some parts of the board the layout has been
changed to emphasize some particular characteristics.
All the analogical circuits are made using discrete components, and have a large-pass band and low-feedback factor.
Only the Highest-quality passive components have been used; lowest-tolerance metallic layered resisters (MIL
standard); low-tolerance, non-polarized polyester/propylene condensers; high-speed, low-loss, high capacity electrolytic
condensers; organic-electrolytes, low-capacity electrolytic condensers.
The integrated-resistance network volume controls used have no buffer for maximum sound transparency.
Analogical circuits with separated components, large pass band and low counter-reaction.
Highest-quality passive components; lowest-tolerance metallic-layered resisters (MIL standard); low-tolerance, non-
polarized polyester/propylene condensers; high-speed, low-loss, high-capacity electrolytic condensers; organic-
electrolyte, low-capacity electrolytic condenser.
Integrated-resistance network volume controls with no buffer for maximum sound transparency.
Offset-recovery circuit.
Multiple source system control: front panel, IR remote control, RS-232 interface.
Microcontroller system control.
High-contrast VFD display. High-resolution selector encoder.