Parasound's New Feature-Rich Monster Monoblocks

by The Audio Beat | January 17, 2020

he John Curl-designed Parasound Halo JC 1+ ($8495 each) is a powerful -- 450 watts into 8 ohms -- mono amp that operates in pure class A up to 25 watts and class AB to full power. The amp replaces the highly praised and long-standing JC 1, but the new amp, at 83 pounds, outweighs the old by 30 percent, and its new power transformer has 20 percent higher capacity. The new amp features additional Nichicon power-supply filter capacitors that increase capacitance from 132,000uF to 198,000uF. The JC 1+ uses 24 Sanken 15A/230V output transistors compared to 18 for the older design -- a 33 percent increase in peak current.

The Halo JC 1+ is the first commercially built product to employ active high-frequency noise filtering via Bybee Music Rails. In another first for the JC 1+, FR-408 printed circuit boards are used for the input and driver stages. Until now FR408 was used for super-computer and aerospace applications. Circuit highlights include an input-stage power supply totally independent from the main power supply. Its R-core transformer isolates sensitive circuitry from high-frequency power-line noise. The Wilson Audio REL capacitors used feature a proprietary design that resists micro vibrations.

Finally, the Halo JC 1+ features a fast-start bias circuit that enables it to sound its best within minutes after turn-on. A bias-level selector switch enables cooler operation, with, according to Parasound, "virtually no performance compromise." To optimize performance with high-gain preamps and high-sensitivity speakers, a two-position toggle switch selects 23dB or 29dB of gain.