Transients on startup

Tech Note: TN0040
Product: RP
Version: All
Date Added: 2002-08-16

Issue

The RPx devices generate a momentary transient (10 V) on analog output channels when they are powered ON, when the hardware is reset, or when a circuit is loaded. When a transducer is connected to the RPx device the transient can be heard as a brief pop or click.

Workaround

If you have a PA5 module, you can connect the RPx output to the transducer through the PA5 and follow the steps below to set the PA5 start-up attenuation setting to 120 dB so that the noise is muted to the maximum.

  1. Turn ON the PA5 and press the Select knob once.

  2. "Atten" should appear in the display screen.

  3. Rotate the knob until the value is set to 120.0, then press the Select knob to accept the value.

  4. Rotate the knob again until the display reads "Save PS", then press the Select knob once.

  5. "Preset-1" should appear in the display screen. Press the select knob again to accept the setting.

  6. "Saving" should appear in the display screen.

If you do not have PA5, you can reduce the click noise by adjusting the gain setting on the external amplifier or by waiting until the circuit is loaded to the RPx device before connecting or turning on the external amplifier.