The Radial J48 is a great-sounding active direct box that has been optimized to produce maximum headroom while working within the limited current available from standard 48V phantom power. By employing a unique switching power supply, the J48 is capable of peak transients to 9 volts without choking. The result is lower harmonic distortion, half the inter-modulation distortion and significantly improved dynamics over other DIs. Features include a -15dB pad, 180 degree polarity reverse, a unique merge function to mix two signals to mono, an 80Hz high-pass rumble filter, and ground lift. Like all Radial products, the J48 is built to handle the abuse on the road and features a unique welded I-beam construction for years of trouble free performance. The single most important development goal of the Radial J48 was increasing the headroom without compromising sound quality. To this end, every possible effort was made to deploy the limited energy resources of phantom power to the audio signal path. To begin, phantom power is converted using a super-efficient digital switch-mode power supply that steps up the internal rail voltage to an impressive 10 volts. This allows one to hit the J48 with as much as 9-Volts without choking! To further increase available horsepower, all non-essential devices such a power-hungry LEDs are turned off when the J48 is in use. A typical LED requires almost as much current as does the complete audio circuit! Welded I-beam construction makes it impossible to torque the PC board. This virtually eliminates cold solder joints, the number one cause of system failure in the field.