DVA R2X single-ended to differential converter

The DVA R2X is a single-ended to differential converter (i.e., unbalanced to balanced converter) for audiophiles. It's the perfect solution for using single-ended preamps with differential (i.e., balanced) power amplifiers, including our own. It has one stereo pair of RCA input jacks and a stereo pair of XLR output jacks. It has a gain of two (i.e., one volt input will yield two volts output) and a maximum output over 20 volts (zero to peak). Audio circuits In designing the DVA R2X, we prioritized the needs of typical audiophiles over the pro-audio requirements found with similar solutions. No options were off the table, including expensive transformers, purpose-designed IC solutions, and our own custom architectures. In the end, the solution we found to be the most transparent for most audiophile applications was a relatively simple custom circuit using carefully selected high-performance audio opamps. The result is incredibly clean and musical conversion for situations that don't involve cable runs of hundreds of meters through challenging EMI environments. Layout and power supply The DVA R2X is built into a compact 7" x 5" x 2.5" chassis. The power transformer is supplied as a separate “wall wart”, so no significant AC noise is brought inside the chassis. The internal power supplies use heavily filtered linear regulators for extremely low power supply noise. Specifications Inputs: One stereo RCA pair designed for consumer line-level signals. Input impedance: 43 kΩ Outputs: One XLR stereo pair, pin 2 hot. Output impedance: 200 Ω Maximum output level: 20 Vzero-to-peak Minimum output load: 4 kΩ differential (2 kΩ per hot/cold output). Differential gain: 2 (6dB) Power: 16VAC, 200mA