Owner's Manual

13
common AC outlet or power strip, you’ll avoid the problems created by resistance in the
house’s wiring.
Hum and buzz is also caused when unwanted voltage flows through multiple component
ground points called ground loops. Here are three tips to avoid ground loops:
1. Your Cable TV or Satellite receiver box might require a Cable TV ground isolator.
2. Use balanced input lines with your Parasound A 52+. (See Balanced and Unbalanced
Lines in this section).
3. When rack mounting, always use the insulated “shoulder” washers on both the front and
rear sides of the rack mount before attaching its bolts to the equipment rack rails. These
break the ground loops caused by metal-to-metal contact between the rack, the components,
and their rack-mount bolts. Extra washers are available from any rack manufacturer
Bare Speaker Wire Ends
If you plan to connect your speaker cables 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 vertically through each terminal’s metal post. Before
inserting the wire, twist its bare strands tightly to prevent any of the individual strands from
making contact across the red plus and black minus 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 52+ 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 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 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 52+ 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 double-sided
circuit boards are FR4 glass epoxy for long-term durability. The chassis is made of heavy
gauge 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.