Parasound Halo T 3 - Manual (Page 25)

PARASOUND T 3 DESIGN OVERVIEW
Circuit Path Topology
For superior sensitivity performance, we use a multi-
gang front-end and discrete multi-stage RF circuits.
The IF bandpass circuit employs hand-picked Murata
filters to achieve high selectivity without increasing
distortion. Only precision components are used in the
detector circuit to accurately extract the analog audio
signal. The audio signal path employs the newest
Burr-Brown OPA 2134 FET integrated circuits for
virtually all gain functions. They are laser-trimmed for
precision and boast incredibly low noise and
distortion specifications. We operate the OPA 2134s in
pure class A for the linear performance and musical
characteristics, without fatigue and harshness.
Functionality
The T 3 has a very elegant user interface with an easy-
to-use remote control handset and simplified front
panel control and status display. The remote provides
convenient control over both the Parasound T 3 Tuner
and the matching P 3 Preamplifier. The RS232, IR
input and DC triggers facilitate system integration into
any multi-zone, multi-room application to make the T
3 as functional as it is great-sounding.
Component Selection
Every component within the T 3 was carefully chosen
for its sonic accuracy and reliability. A precision front-
end assures excellent tuning characteristics. Premium
filters are selected for outstanding selectivity and low
distortion. Metal film resistors with 1% tolerance are
incorporated throughout because of their precision
and because their values don’t drift as they heat up
during operation. Semiconductors were selected for
superior performance in their specific roles in the
circuit – specifically their low noise and distortion
characteristics plus low DC offset. Gold has the best
conductivity characteristics of any metal, so we use
only high quality gold-plated input and output
connectors. The circuit boards are made of FR4 glass
epoxy for their long-term durability, while circuit
layouts are optimized for RF frequencies. The chassis
is made of heavy gauge steel to safely protect and
shield the internal circuitry. This attention to detail
when selecting electronic components makes the
difference between a very good and an outstanding
performing tuner.
The Power Supply
The T 3 power supply begins with a large toroidal
power transformer that is chosen for its efficiency,
low hum field, and high current rating. Encapsulating
the power transformer in an epoxy filled steel canister
assures ultra quiet performance. The audio signal
path circuits and the switching/control circuits have
independent closely regulated power supplies. This
preserves the purity of the audio signal by preventing
interference between the circuits. We also use a hand
made detachable audiophile-grade AC cord to deliver
the AC voltage to the power transformer.
To create the DC voltage, we use high-speed rectifier
diodes and famous Nichicon electrolytic capacitors
that are chosen for their low ESR and dielectric
absorption. In addition, these filter capacitors are
bypassed with polypropylene capacitors to help
reduce ripple and to eliminate noise and interference
that is generated in AC power lines from computers
and other appliances in the home.
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