INTRODUCTION
The
HV trenta
amplifier begons on the new family of high performance car amplifiers
and other devices called
THESIS
.
It is endowed with highly innovative technologies and circuit solutions and its realization
required big efforts and investments for research and development.
The purpose was to realize an amplifier that had to be a "milestone" in the evolutive history
of
AUDISON
products.
Its structure in the circuit layout can be identified at two levels: the first one (power) is
entirely on the mother circuit board and it collects all components which handle high
currents and need warmth dissipation; the second one (signal and control) is located on
special surface mounting devices which perform all complex functions of the whole
device.
This peculiar design technique allowed the study and optimization of the signal paths and
the blocking of the interactions among the different stages.
The
HV trenta
amplifier is constituted by three main parts: preamplifier, final power
stage and power supply.
PREAMPLIFIER
HV trenta
amplifier is supplied with an independent preamplifier unit, where the general
sensitivity can be adjusted in the 0.2
÷
1V range.
This unit can be disactivated, allowing the connection with an external preamplifier.
The input signal is applied to ABS (Audison Balanced System) connector in balanced or
unbalanced way, and to MA-1X module through two polypropylene capacitors.
MA - 1X circuit, which constitutes the input interface for audio signals, is characterized
by a FET- BJT hybrid circuitry in CASCODE configuration and it has been superintegrated
in a single chip whose features are: max power supply:
±
50 VDC, S/N ratio: 125 dBA,
Slew Rate: 120 V/
µ
S, Bandwidth: DC
÷
1MHz.
FINAL POWER STAGE
Balanced or unbalanced audio signal (it can be selected) applied to the input can directly
drive the final stage without the preamplifier interposition.
By disactivating, the preamplifier, the final stage sensitivity can be between 1.0
÷
5 V.
The signal coming from the MA-1X module arrives in balanced connection to the
V-AMP 12 LV module which makes the driving of the final stages in voltage and the
thermic stability control.
The internal circuit is characterized by a double complementary differential amplifier in
CASCODE connection with FET-BJT and current mirror combination. This circuit is
integrated in two custom chips (CDAP - CDAN) whose components undergo a laser trim
for the maximum tolerances reduction.
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REGULATIONS
All controls are located on top of the device.
- MONO ON-OFF: see MONO connection.
- BALANCED-UNBALANCED: see balanced-unbalanced connection.
- PREAMP ON-OFF: see connection to external preamplifier.
- L-R LEVELS: amplifier sensitivity adjustment , separated for the two channels.
PROCEED AS FOLLOWS
Adjust the device according to the head unit requirements, through the above
mentioned controls and regulations.
1) Set the two L-R LEVELS potentiometers towards minimum (counterclockwise).
2) Turn the head unit volume control to about 3/4 of its maximum volume.
3) Set the two L-R LEVELS towards maximum sensitivity until you get sporadic
lighting of PEAK R-PEAK L leds with high dynamic musical passages.
IMPORTANT: if you should hear distortion phenomena without the PEAK L-R leds
lighting up, it means that a distorted signal is coming from the head unit. In this case,
turn the head unit volume down until there’s no longer any distortion. Repeat
calibration operation omitting step 2.
PROTECTIONS
The device is provided with several electronic protections which protect the amplifier
from dangerous or wrong functioning conditions , avoiding to interfere with the music
signal in order to get the best performances in every condition.
- Outputs protection: any type of short circuit on the speaker wires , be it between
themselves or to ground , will cause no damages.
- Temperature protection: anomalous use conditions or high ambience temperature
(above 60
°
C), that doesn’t allow the amplifier to discharge the produced heating
(maximum working temperature of the device 80
°
C), causes the protection intervention.
- Protection against inverted polarity of the power supply: if the power supply cables
polarities should be mistakenly inverted, the electronic circuitry will be protected by
burning the external fuse, that will have to be replaced with an identical one.
- Protection against continuous current in the output.
- Protection against excessively low or dangerous loads.
A front red LED (SAFE) indicates intervention of protection circuits. Once the cause
of malfunctioning is eliminated, you need to turn head unit off and turn it back on in
order to have the device function again. The amplifier will function normally.
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