|Parasoundís New John Curl Designed Halo Power Amp|
|Home Theater News Power Amplifier News|
|Written by AVRev.com|
|Thursday, 29 August 2002|
Parasound has introduced its highly-anticipated 400-watt JC 1 monoblock power amplifier as the flagship amplifier for its new Halo line of premium audio components. With impressive current reserves, the amplifier delivers 800 Watts into 4 Ohms, and 1200 Watts into 2 Ohm loads. This extremely powerful component was developed by Parasound in collaboration with legendary designer John Curl’s CTC Builders, and represents the culmination of 13 years of Curl's ongoing evolution of Parasound power amplifier topologies.
Formed in 1998, CTC Builders consists of John Curl handling electrical design, board and layout design by Carl Thompson, and Bob Crump's component selection and implementation. The trio has developed a number of products, including the CTC Blowtorch preamplifier and the CTC BBQ amplifier.
The JC 1 was conceived as a signature product, growing out of CTC's modifications of the Parasound HCA 3500 amplifier which was sold between 1999 and 2001. With various changes to the design, including a much larger heatsink and double the power supply, as well as component and layout alterations, the monoblock JC 1 is priced at $3,000.
The heart of the JC 1 power supply is a large toroid transformer rated at 10 Amperes continuous, backed up with four enormous 33,000-microFarad Nichicon Gold Tune electrolytic filter capacitors, which Curl believes to be the finest in the world. The tremendous inrush of current required to charge 132,000 microFarads of capacitance requires a specially designed relay-bypassed "soft start" circuit to prevent tripped circuit breakers. Through meticulous board design and component placement, as well as massive aluminum heatsink, the amplifier operates without the need for unnecessary cooling fans.
Curl's complementary JFET and MOSFET configuration for the input and driver stages respectively provide pure class A operation in these parts of the circuitry. Nine pairs of high current bipolar transistors in the output stage provide up to 25 Watts of pure Class A -- more than that of amplifiers selling for several times the price of the JC 1. Only during extremely loud musical passages or large bass transients, such as special effects 'explosions,' does the JC 1 enter Class AB operation.
The JC 1 power amplifier features silver cabinetry common to the entire Halo line.