1. Your Cable TV or Satellite receiver box might require a Cable TV ground isolator.
2. Use balanced input lines with your Parasound A 31. (See Balanced and Unbalanced Lines in this section).
3. When rack mounting, always use the insulated “shoulder” washers. These break the ground loops caused by
Bare Speaker Wire Ends
If you plan to use connections with bare wire ends, use a wire stripper to remove just enough insulation to expose a 1⁄2" (13 mm) length of bare wire. You can insert the stripped wire into the hole that goes sideways through the terminal’s metal post. Before inserting the wire, twist its bare strands to prevent any of the strands from making contact across the two speaker terminals. If you have a soldering iron, you can “tin” (apply a small amount of molten solder) to each stripped bare wire to prevent it from unraveling, fraying and oxidizing.
Parasound A 31 Design Overview
Circuit 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
As our featured amplifier designer since 1990, he has created many products that have earned Parasound worldwide acclaim. 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 within the A 31 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
The Power Supply
The heart of the power supply is a 1.5 kVA toroid power transformer, chosen for its efficiency, low hum field, and high power rating. Encapsulating this massive power transformer in an
The A 31 power transformer employs multiple independent secondary windings so that each amplifier channel has its own power supply, assuring more than ample DC voltage at all
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