Lab.gruppen APD (Auto Power Down) feature
This article describes the use of the Auto Power Down (APD) feature in the Lab.gruppen D Series Tesira amplifiers.
Energy Star compliance
The APD feature is included to allow the amplifiers to qualify for the highest EU energy conservation compliance rating by having a true "off" that they can achieve automatically.
There are 2 user definable settings to be made for the APD option to function.
Within the Tesira Lab.gruppen block you will see an "APD timeout (min)" setting, where (min) denotes minutes. Integer values between 0 and 60 are accepted. The default value is 0, meaning APD has been bypassed. Any other timeout setting will enable APD.
There is also an "APD Threshold" which is definable for each channel of the amplifier. Values between -100 and 0 dB are accepted, in 1/10 dB steps. The default value is -40.0 dB.
The APD circuit monitors for input signal. When input signals fall below the APD Threshold value the APD timer begins to run. The timer will reset if signal levels exceed the threshold. When the timeout value is met the APD circuit triggers and powers the amplifier off (Sleep).
To re-awaken the amplifier, you can either touch the power button on the front panel, or provide a contact closure between logic pin 1 and the ground pin on the Logic IO of the amplifier. An amplifier in Sleep displays "Not Available" in the status button. The amp is not discoverable on the network and does not respond to command traffic via RS-232 or telnet (TTP) protocols because it is off.