Audio Format Converter

The RDL RU-AFC2 is a two-way audio format converter designed to interface unbalanced RCA lines with balanced audio systems. One section accepts two unbalanced line-level channels through left and right RCA phono jacks and provides balanced left, right, and summed mono outputs. The other section accepts balanced left and right signals through XLR connectors or a detachable terminal block and supplies unbalanced left and right RCA outputs. Front-panel connections, level controls, and metering keep routine setup accessible, while rear-panel terminal blocks support fixed wiring.

Ideal Use Cases

Use the RU-AFC2 when a stereo RCA source must feed balanced equipment, when balanced stereo audio must connect to RCA inputs, or when a summed mono feed is needed alongside balanced left and right outputs. Its combination of front-panel RCA and XLR connectors with rear-panel detachable terminal blocks accommodates both accessible patching and installed wiring. The one-third-rack format also suits high-density rack mounting where multiple conversion or interface devices must occupy limited rack space.

Why Choose This Model

The RU-AFC2 combines unbalanced-to-balanced and balanced-to-unbalanced conversion in one unit. Front-panel multi-turn LEVEL trimmers provide separate adjustment for the conversion sections, while a dual-LED VU meter for each channel supports level monitoring. A switch-selectable ground lift is provided for the XLR output jacks. Gold-plated connectors, balanced mono summing, and multiple connector formats further distinguish the unit from a basic point-to-point converter. Recommended PS-24AS USA and PS-24AX international power supplies are not included.

Installation and Integration

For unbalanced-to-balanced conversion, the two RCA inputs accept unbalanced line-level signals up to +25 dBV. The three balanced outputs provide left, right, and mono-sum signals at +4 dBu, with a stated maximum of +25 dBu. Left and right outputs are available through two XLR connectors and/or a detachable terminal block, while the mono sum is available through a detachable terminal block. Gain adjustment is specified from 25 dB to +9 dB relative to +4 dBu.

For balanced-to-unbalanced conversion, left and right inputs connect through two XLR connectors or the detachable terminal block. The section is referenced to a +4 dBu input feeding −10 dBV, with unbalanced left and right RCA outputs rated to a +17 dBV maximum. Level adjustment spans −28 dB to +5 dB relative to −10 dBV. The unit requires ground-referenced 24 Vdc power at 60 mA while idle and 100 mA maximum. Its specified operating environment is 0° C to 55° C.

Performance Highlights

The RU-AFC2 has a specified frequency response of 10 Hz to 150 kHz within ±0.25 dB. THD+N is less than 0.005%, and noise is specified below −90 dB relative to +4 dBu. Crosstalk is below −80 dB from 20 Hz to 20 kHz, while available headroom exceeds 20 dB. For the balanced-to-unbalanced section, common-mode rejection is greater than 80 dB from 50 to 120 Hz. These figures define its handling of bandwidth, distortion, channel separation, operating margin, and common-mode signals.

What Makes It Different

The additional balanced summed-mono output expands the RU-AFC2 beyond conventional stereo conversion. It can provide balanced left and right feeds plus a mono sum from the same unbalanced stereo input section. Connection flexibility is another defining feature: unbalanced RCA and balanced XLR connections are located on the front panel, while balanced detachable terminal-block connections are provided on the rear. The XLR output ground-lift selection, multi-turn level controls, per-channel dual-LED VU meters, and one-third-rack construction place conversion, adjustment, monitoring, and installation options in a compact format.

Final Assessment

The RDL RU-AFC2 is suited to systems that require conversion in either direction between unbalanced RCA and balanced XLR or terminal-block audio. Its balanced stereo and mono-sum outputs, adjustable levels, visible channel metering, selectable XLR ground lift, and documented performance make it a precisely specified interface for installed or rack-mounted audio paths. The broad 10 Hz to 150 kHz frequency response, greater than 20 dB headroom, and less than 0.005% THD+N are central performance attributes.