Radial Engineering Space Heater 500

Radial Engineering Ltd is pleased to introduce the Space Heater 500, a single-valve overdrive module for the Radial Workhorse and other 500-series racks that provides a natural crunch for drums, adds character to vocals, and natural compression to bass and acoustic guitar.

The design begins with a single 500 series module in a fully enclosed steel enclosure. This not only protects the electronics, but prevents outside interference from creating noise, and the Space Heater 500 from originating hum due to the high voltage required by the 12AX7 tube. This, in fact, is part of the magic. A 3-position HEAT switch allows the user to choose between 35 volts, 70 volts or 140 volts for the desired level of tube distortion. Distortion is further adjusted using a combination of a drive control and a level control to raise the gain. Voltage is generated by an internal charge pump while the 16-volt power supply of the Workhorse or 500 Series provides the 12 volts needed to heat the 12AX7 tube. A Jensen transformer is employed at the output to give a more vintage character to the signal path while benefiting from galvanic isolation to reduce hum and noise caused by ground loops.

To further refine the sound response, the Space Heater 500 is equipped with high-pass and low-pass filters. These allow the engineer to concentrate the tube effect on a particular frequency band or distribute it if necessary. EQ can also be applied to the pre- or post-valve signal path for greater tonal flexibility.

Since the Space Heater 500 employs a high-voltage tube circuit with a current draw of 235 mA, a special power assignment switch is available adjacent to the on-board connector to balance the draw when used with most 500-series racks.