Portable Audio Signal Generator

Ideal Use Cases

The RDL PT-ASG1 is a portable or bench audio signal generator for workflows that require a stable reference signal at microphone, professional line, or consumer output levels. Its nominal 700 Hz oscillator is suited to checking audio signal paths, comparing levels, and supplying a repeatable reference during system setup or troubleshooting.

Two connectorized outputs support common audio interfaces. The balanced XLR output is selectable from the front panel for microphone- or line-level operation, while the unbalanced phono output provides a consumer-level signal. This combination makes the PT-ASG1 useful when work moves between balanced professional equipment and unbalanced consumer equipment.

Why Choose This Model

The PT-ASG1 combines multiple reference levels with output stability specified as better than 0.01 dB. Its professional line output can be set for +4 dBu or +6 dBu into a 2.5 kΩ load. The +4 dBu setting is the factory configuration, while the reference-level preset supports selection of +4 dBu or +6 dBu.

For microphone-level testing, the balanced output is set to -46 dBu, which is 50 dB below the +4 dBu reference. The output network is designed to produce the same level when connected to low-impedance 200 Ω microphone preamps or higher-impedance preamps above 1 kΩ. The unbalanced phono output is specified at 10 dBV.

Installation and Integration

Integration begins by selecting the required output connection and signal level. Use the XLR output for a balanced microphone- or line-level connection, then set the front-panel level selector for the intended application. Use the phono connection when an unbalanced consumer-level output is required. The nominal 700 Hz oscillator provides the reference signal without requiring a separate signal source.

The PT-ASG1 supports both portable and fixed bench operation. It can operate from an internal standard 9 V battery or from an external 12 to 30 Vdc supply drawing 20 mA. A 24 Vdc source falls within the specified external operating range. This power flexibility allows the same generator to be used away from a fixed power connection or incorporated into a powered workbench setup.

The specified ambient operating range is 0°C to 50°C. No battery, external power supply, cables, or other accessories are identified in the supplied product data, so system requirements should be matched to the listed connections and power specifications.

Performance Highlights

At the center of the PT-ASG1 is a nominal 700 Hz oscillator with output stability better than 0.01 dB. The balanced line output supplies either +4 dBu or +6 dBu into a 2.5 kΩ load, providing two precision reference-level choices. The microphone setting supplies -46 dBu into a 2.5 kΩ load and is defined relative to the +4 dBu line reference.

The two-output design covers balanced and unbalanced signal paths without changing generators. The XLR connection addresses professional mic- and line-level inputs, while the phono connection addresses consumer-level equipment. Front-panel mic or line selection keeps the primary balanced output configuration directly accessible during testing.

What Makes It Different

The defining feature of the PT-ASG1 is its combination of portability, bench operation, precise level references, and support for three practical output categories. Instead of limiting operation to one balanced level, the unit offers selectable microphone or line output through XLR, with +4 dBu and +6 dBu line references available. A separate phono output extends its application to unbalanced consumer-level connections.

Its microphone output network also addresses differing preamp input impedances. The specified level remains the same with 200 Ω and greater-than-1 kΩ microphone preamps, helping preserve the intended reference across the stated range of connected input types.

Final Assessment

The RDL PT-ASG1 is a focused reference generator for audio systems requiring a nominal 700 Hz signal, balanced XLR mic or line operation, and an unbalanced phono output. Its better-than-0.01 dB output stability, selectable +4 or +6 dBu line reference, -46 dBu microphone level, and battery or external DC operation make it well matched to portable testing and permanent bench use. It is an appropriate choice when stable, predefined audio levels are more important than variable-frequency operation.