Parasound HALO JC 1+, Руководство пользователя

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Parasound JC 1+ Design Overview
Circuits Designed by John Curl
Parasound design consultant John Curl has been a legend among audiophiles and electronic engineers
for decades. He pioneered measurements to correlate musical accuracy with the materials used in parts,
worked with world-class touring companies, has designed highly coveted audio classics, including the original
Mark Levinson JC-2, Denneson JC-80, Vendetta Phono Preamplifier, and CTC Blowtorch preamplifiers;
master recorders for Wilson Audio and Mobile Fidelity; and the mixing consoles used in live concerts by The
Grateful Dead and the Montreux Jazz Festival in Switzerland.
As our featured amplifier designer since 1990, he has also created many products that have earned
Parasound worldwide acclaim and favor, including the Parasound Halo JC 1, JC 2/JC 2 BP, JC 3, JC 3+, JC
3 Jr and JC 5. John is particularly proud of what he and Parasound have accomplished together: “The circuits
I design for Parasound are extremely sophisticated and are typical of products that are far more expensive. I
can’t think of any other audio products that offer nearly as much bang for the buck.”
Parts Selection
Every part in the JC 1+ is carefully chosen for its accuracy and reliability. Metal film resistors with 1%
tolerance are selected for their precision and because their values don’t drift as they heat up during operation.
Polypropylene and mica capacitors are used extensively for their superior linearity and low dielectric
absorption. Semiconductors are selected for superior performance in their specific roles in the circuit. Gold
has the best conductivity of any metal, so we use high quality gold-plated input connectors and speaker
terminals. The main circuit boards are double-sided FR4 glass epoxy for long-term durability. The material of
the input-driver stage circuit board is FR408 which was developed for super-computers and is superior to
other circuit board materials especially for high frequencies. The chassis is made of heavy gauge aluminum
and steel to safely house the internal circuitry. This attention to detail when selecting parts makes the
difference between a very good amplifier and an outstanding amplifier.
The Output Stage Power Supply
The heart of the power supply is a 2.1 kVA toroid power transformer with a special premium grade steel
core chosen for its efficiency, low hum field, and high continuous power rating. Encapsulating this massive
power transformer in a steel canister filled with epoxy prevents mechanical vibrations, assuring ultra-quiet
performance.
The JC 1+ Input Stage Power Supply
It all starts here because the input stage determines the “sonic signature” of an amplifier. Most amplifier
designers don’t realize that even the most minute distortions created within the input stage are the most
insidious because they are amplified by the output stage. A major cause of this distortion is whenever the
input stage voltage sags whenever the output stage is working hard and pulling down the voltage of the input
stage. To prevent any distortion originating in the input stage, the JC 1+ has an independent input stage
power supply with its own R-core power transformer. The 110V B+ and B- voltage rails cannot sag under any
condition, virtually eliminating distortion, regardless of how hard the output stage is working. The independent
driver power supply for the input stage employs premium Nichicon Gold capacitors totaling 4,440uF per
channel.
Extra Filtering
The JC 1+ input stage power supply also employs two Bybee Music Rails™. These are sophisticated
active filters that “scrub” the last vestige of high frequency noise from the input stage B+ and B- rails. We do
not know of any other commercially available amplifier that uses them and many probably don’t know they
exist. Music Rails™ were invented by a Silicon Valley microwave genius, in collaboration with John Curl and
Carl Thompson, Curl’s circuit board designer.