Radio Design Labs RDL-SF-NP50AX

Availability: Available Unavailable

Product Type: Pro Audio

Product Vendor: Radio Design Labs

Product SKU: RDL-SF-NP50AX

Overview 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...

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ATTENTION! TARIFFS AND INDUSTRY IMPACT: All Pricing is subject to change without notice due to industry wide Tariff increases with several major manufacturers. Please check with your sales rep for current and updated pricing information prior to ordering. Quotes are only valid for the day they are provided. Returns for credit - New product may be approved to be returned for credit within 30 days of original packaging. Product must be new, unopened and in original packaging Returns and canceled orders are subject to a 25% restocking fee. -MANY ITEMS ARE CURRENTLY ON BACKORDER. PLEASE VERIFY PRICING AND AVAILABILITY ON ALL PRODUCTS WITH YOUR SALES REP VIA CHAT, EMAIL, OR PHONE BEFORE PLACING AN ORDER

Product Details


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 k? 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.

The module is equipped with both thermal and output short-circuit protection. The high-efficiency Class D output stage produces minimal heat for all levels of expected voice or music modulation. Upon power-up and during overloads or overheating, an LED MUTE indicator glows yellow and the output is muted. Valid synchronization to the Dante network is indicated by a green LED visible from the front of the unit.

The SF-NP50A is equipped to operate from an included external 24 Vdc power supply. The SF-NP50A monitors the amplifier power and limits the current to protect the power supply from shutting down even during extreme feedback or square wave modulation conditions. A red rear-panel OVERLOAD PROTECT LED flashes when the SF-NP50A reduces power consumption to prevent shutdown of the power supply.

The SF-NP50A is constructed in a durable, professional all-metal enclosure suitable for free-standing, surface-mounted or rack-mounted operation. This full-featured SYSFLEX product is engineered and manufactured in the U.S.A for continuous duty in demanding installations. The versatility of SYSFLEX products adds enormous flexibility in the design and installation of professional A/V systems.


  • 50 Watts RMS Constant Voltage Amplifier
  • 70 V or 100 V Output
  • Plenum Rated per UL 2043 Standard
  • Converts One Dante Network Audio Signal to a Mono Constant Voltage Output
  • Selectable Dante Sample Rates: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz
  • 0 dBFS Input for 50 W Output
  • Analog Balanced Mono Input or Unbalanced Mono Mini-Jack Input
  • Automatic Ducking Controlled by Network or Analog Input (Switch-Selectable)
  • Ducking Attenuation -25 dB or "off" (Switch-Selectable)
  • Balanced Line Output from Network Audio Source
  • Automatically Limits Supply Current to Protect Against Power Supply Shutdown
  • VCA Control on Detachable Terminal Block
  • External Control Using 10 k? Potentiometer or 0 to 10 Vdc
  • Compatible with RDL Remote Level Controls
  • Special Software Not Required for Module Setup
  • LED Indicators: Network Sync, Amplifier Mute, Analog Input Level, Ducking Threshold
  • High-Efficiency Class D Operation
  • Thermal and Short-Circuit Protection


Inputs (2) Dante network (1 channel), Analog audio
Network Input Section
Network Connector RJ45 with Link and Speed indicators
Digital Audio Ethernet Protocol Dante
Transmission Rate 100 Mbps
Sample Rates Supported 44.1 kHz, 48 kHz (default), 88.2 kHz, 96 kHz
Bit Depth Supported 24 bits
Analog Section
Analog Input Connectors (2) Balanced on terminal block or Mono unbalanced Mini-Jack (L and R inputs summed to mono)
Balanced Input Level +4 dBu nominal, adjustable; -10 dBu minimum (for 20 dB below full output power); +25 dBu maximum (before clipping)
Unbalanced Input Level -10 dBV nominal, adjustable; -25 dBV minimum (for 20 dB below full output power); +10 dBV maximum (before clipping)
Gain Adjustment Single turn audio taper (with associated Dual-LED VU Meter calibrated to 20 dB below full output power)
Input Impedance >10 k? balanced, >5 k? unbalanced
Common mode rejection > 60 dB (50 Hz à 120 Hz)
Ducking/Muting Actuation Automatic (Rear-panel adjustable signal threshold with LED indicator)
Ducking/Muting Release Delay 4 seconds, nominal
Ducking/Muting Source Switch-selectable priority for network or analog input
Ducking/Muting Level Switch-selectable for 25 dB ducking attenuation (nominal) or OFF
Reference Level (network input) 0 dBFS = 50 W
Power Amplifier Output 50 W RMS (70 or 100 V)
Frequency Response +0/-3 dB (50 Hz to 20 kHz)
THD+N < 1% (1 kHz)
Noise <-85 dB (below max power); <-75 dB (below 1/8 power)
Line Output +4 dBu balanced (for -20 dBFS)
Frequency Response +/- 0.3 dB (20 Hz to 10 kHz); +/- 2 dB (20 Hz to 20 kHz)
Noise <-70 dB (below +4 dBu)
Indicators (8) Front-panel: Sync (green), Amplifier muted (yel), Rear-panel: Overload Protect (red), Ethernet Link and Speed (2), dual-LED VU meter (2), Ducking threshold
VCA 0 to 10 Vdc control, detachable terminal block (compatible with RDL VCA wall controls)
Ambient Operating Environment 0° C to 40° C Maximum; 20° C Recommended
Power Requirement 24 Vdc @ 2700 mA
Power Supply (included) 100 to 240 Vac, 50-60 Hz, IEC C14; Output to module: 24 Vdc
Plenum Rating Standard UL 2043
Dimensions Height: 1.7 in. (4,32 cm); Width: 5.83 in. (14,8 cm); Depth: 6.45 in. (16.38 cm)
Package Type Cardboard Box
Package Dimensions 10 x 7 x 2.25 in
Shipping Weight 4.22 lbs.
WEEE weight 3.82 lbs.
Tariff code 8518.50.0000

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