General informations
RIAA preamplifier - Equalizar stage
This stage consists of two CABRE RM-02 operational amplifiers modules, well known among the audiophiles for their excellent electric and musical performance.
Each RM-02 module is individually calibrated and tested (main data are reported on it), it is drowned in epoxi resin to ensure insensitivity to vibrations, dust, dampness and great thermal stability.
Particular care was also taken in the cartridge-phono input stage interfacement to obtain perfect frequency linearity by compensation between mechanical and electrical resonance. Such compensation is reached by compensating the capacitive component of cartridge impedance: a built-in microswitch allows to change load capacitance from 100 to 470 pF by steps of 50 pF each.
Attenuation of radio-frequency disturb demodulated at the phono input is achieved in two ways: by SID (Slewed-Induced-Distorsion) elimination and optional insertion of filters through built-in microswitches.
Power supply section
The power supply stage in AS-201 incorporates a ligh efficiency toroidal transformer and a sofisticated-discrete component-stabilization circuit.
Steel alloy shielding of transformer unit and the heavy filtering of its circuitry reduce mains components in power supply to non-measurable levels.
Stereophones and line amplifier
Many manufacturers neglect phones output on preamplifiers in favour of a greatest appeal for the power amplifier unit. AS-201 incorporates a stereophones amplifier featuring excellent specification, comparable with those of the other amplification stages. In particular it can drive any stereophones at its best, regardless of impedance and efficiency.
Particular care was taken in the development of line amplifier stage as nowadays top quality level signals are available at line input jacks (TUNER, DAD, AUX).
CD player input consists of a low noise operational amplifier with high speed operation and low distortion capable of performances even of higher quality than those of digital recording/reproduction systems.
Product quality
AS-201 is manufactured of premium quality components and materials to ensure reliability, precision and constant service life performance.
Great care was taken in circuital project to obtain a constant signal-to-noise while turning the main volume knob and almost total insensitivity of the unit to outer magnetic fields.
The remarkable versatility of this preamplifier is made evident by the number of possible connection: six input and five output jacks. Besides Phono MM input and line inputs (AUX, DAD, TUNER), this unit features two input/output jacks for the connection of either a tape deck or a signal processor unit.
Materials employed
In particular: glass fibre printed circuit board, 1% tolerance metal film-resistors, 2% polypropylene and polycarbonate capacitors, gold flashed contact microswitches, thick film volume potentiometer, gold plated input and output jacks, directly fixed on a glass fiber printed circuit board (twin face type), to minimize connections through low capacitance flat wire.
Functions
The remarkable versatility of this preamplifier is made evident by the number of possible connections: six input and five output jacks. Besides Phono MM input and line inputs (aux, DAD and tuner), this unit features two input/output jacks for the connection of either a tape deck or a signal processor unit.
Tape dubbing is also possible when two decks are available. The two pre-out jacks allow to use special components requiring a signal whose level is controlled by the preamp volume knob (CABRE AS-46, Time-delay unit, etc.) without cutting direct line between preamp and power amplifier.
The possible exclusion of these jacks (through a control on front panel) and the high performance phones output, make it extremely easy to use this preamp with multi-channel amplification systems or with active speakers.
The mono/stereo switch and the main switch complete the list of controls of the AS-201, this latter also controlling one of the two mains sockets available on rear panel.
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