The SF-NP50A is an audio power amplifier that converts one Dante network audio channel and one analog input to a 70 V or 100 V constant voltage amplified output. The output provides 50 watts for a network digital audio level of 0 dBFS. Special software is not required to configure the module.
An analog audio source may be connected to either the mono balanced terminal block input or to the unbalanced Mini-Jack which sums the left and right channels to mono. Input gain is set by the installer using a rear-panel single-turn potentiometer with an associated dual-LED VU meter calibrated to 20 dB below maximum power output.
Either the analog input or the network audio input may be used as a paging source. A rear-panel switch is used to set which input has priority. That input utilizes an automatic detection circuit with an adjustable threshold indicated by an LED to attenuate by 25 dB or mute OFF the other input as set by a rear-panel switch. The attenuated input fades up to normal volume when the paging message is finished.
The Dante network audio source drives a balanced line-level output on a detachable terminal block to feed the inputs of other audio equipment or power amplifiers. The output level is +4 dBu balanced for a network level of -20 dBFS.
The SF-NP50A is equipped with an internal VCA for setting the amplifier output level. A detachable terminal block provides for the connection of an external 10 kΩ potentiometer or a 0 to 10 Vdc control voltage. RDL remote controls are available to provide single-turn, multi-turn (rotary encoder) or pushbutton (ramp or fixed level selection) user level control. VCA control insures long term noise-free level adjustment.
