Unbalanced to Balanced Converter-2 Channel

Ideal Use Cases

The RDL FP-UBC2 is a two-channel audio converter for routing unbalanced source signals into balanced signal paths. Its two identical circuits support either stereo operation or two independent mono channels, making it suitable when a paired source must be converted together or when two separate signals require the same interface. The output configuration can be balanced or unbalanced, allowing the converter to accommodate more than one downstream line arrangement. Cabinet, shelf, or rack mounting makes it applicable to fixed installations where the converter needs to sit near source equipment, accompany other system hardware, or become part of a rack-based signal chain.

Why Choose This Model

The FP-UBC2 combines two conversion circuits with independent channel adjustment. Separate gain controls allow each circuit to be set individually, with a specified range of 5 dB to +10 dB relative to a +4 dBu output for a −10 dBV input. This arrangement is useful when the two incoming channels require different trim settings. The unit provides a rated +4 dBu output and is designed for low-noise, low-distortion conversion. Its connectorized design and RDL FLAT-PAK format bring conversion, level adjustment, and flexible mounting into one enclosure.

Installation and Integration

The input configuration is unbalanced with an impedance of 10 kΩ. The output is rated at 150 Ω balanced and can drive 600 Ω or 10 kΩ lines; the published output configuration also permits unbalanced operation. Each channel has a separate control, allowing independent setup for stereo or dual-mono use. The FP-UBC2 measures 1.29 inches high by 3.25 inches wide by 4.07 inches long, equivalent to 3.28 by 8.26 by 10.34 cm. It supports cabinet, shelf, or rack mounting.

Power requirements are ground-referenced 24 Vdc at 50 mA. Recommended power supplies are the PS-24AS for the USA and the PS-24AX for international use. A power supply is not included. The rated ambient operating range is 0°C to 55°C. The unit has a published WEEE weight of 0.575 pounds and a shipping weight of 0.725 pounds. Its cardboard package measures 3.625 by 4.625 by 2.125 inches.

Performance Highlights

The published frequency response extends from 20 Hz to 40 kHz within ±0.25 dB. THD+N is specified at less than 0.05%, with a typical figure of 0.01% at 1 kHz, while IMD is less than 0.02%. Noise is rated below −85 dB when referred to +4 dBu across 20 Hz to 20 kHz. Crosstalk is better than 70 dB from 20 Hz to 20 kHz and is typically below −80 dB at 1 kHz.

The rated output level is +4 dBu, supported by more than 18 dB of headroom at that output level. The specified input-level range is 20 dBV to −5 dBV for a +4 dBu output. Together with the 10 kΩ unbalanced input and 150 Ω balanced output rating, these figures define the converter’s operating range for integration into an audio signal path.

What Makes It Different

The defining feature of the FP-UBC2 is its combination of two identical circuits, separate level controls, and a choice of stereo or dual-mono operation. It is not limited to balanced output use because its outputs can also be configured as unbalanced. This provides flexibility when signal requirements change across an installation. The FLAT-PAK enclosure further distinguishes the unit by supporting cabinet, shelf, and rack placement without restricting the installer to one mounting approach. Published specifications cover frequency response, distortion, noise, crosstalk, headroom, impedance, and operating temperature.

Final Assessment

The RDL FP-UBC2 is a focused choice for two-channel unbalanced-to-balanced audio conversion where independent adjustment and documented performance are required. It supports stereo and dual-mono configurations, delivers a rated +4 dBu output, and offers a 20 Hz to 40 kHz frequency response. Balanced or unbalanced output operation and multiple mounting options help it fit varied signal-path layouts. Installation planning should account for the required ground-referenced 24 Vdc power source, since the recommended PS-24AS or PS-24AX supply must be obtained separately.