RDL SF-PA50A 50W 70/100V Audio Amplifier (North American Model)

RDL SF-PA50A 50W 70/100V Audio Amplifier (North American Model)

RDL SF-PA50A 50W 70/100V Audio Amplifier (North American Model)


Show MoreLess


Now Viewing:

Special Order
Expected availability: 7-10 business days

Product Highlights

  • Analog Input to Constant Voltage Output
  • 50W Class-D RMS Power at 70 or 100V
  • Adjustable Input Gain
  • Terminal Block & 3.5mm Inputs
  • Terminal Block Output
  • Supports VCA Control
  • Thermal & Short-Circuit Protection
  • Power via Included 24 VDC Power Supply
  • Durable Metal Enclosure
  • Made in the USA
Show moreShow less

Model: North American, Includes Power Cord

Export, Excludes Power Cord

Special Order

North American, Includes Power Cord

This item is noncancelable and nonreturnable.

B&H $500 Gift Card Dash

Share for a chance to win a $500 B&H Gift Card!

Share on Twitter

Share a favorite product for chances to win one of eight $500 B&H Gift Cards!
1 new winner announced every Monday starting Nov 5th!
Limit 1 entry per day: Come back every day to increase your chance of winning.

Be sure to mention #BHWishList when you share!

Congrats to our winners so far:

Next winner: Dec 17th

James Z. (Wk 1)

Ralph H. (Wk 2)

Arturo M. (Wk 3)

Rich P. (Wk 4)

Valeria A. (Wk 5)

Sabrina B. (Wk 6)

Official Rules


NO PURCHASE IS NECESSARY TO ENTER OR WIN. The B&H $500.00 Gift Card Dash (the "Sweepstakes") is void where prohibited by law and is sponsored by B&H Foto & Electronics Corp., 440 Ninth Avenue, New York, NY 10001 ("Sponsor"). It is not sponsored or endorsed by Facebook or Twitter in any way.

Entry Period/Methods of Entry. The Sweepstakes will run from on or about October 28, 2018 until on or about December 23, 2018 (the "Entry Period"). Entries received outside the Entry Period are void. Enter the Sweepstakes via either one of the following methods. (1) Share any product found on the B&H website (the "Website") on Facebook or Twitter via the dedicated links contained on the website using the hashtag #BHWishlist; or (2) Mail a postcard (postmarked during the Entry Period) containing your name, address, phone number, and email address, and indicate the subject(s), if any, about which you are interested in receiving future emails from B&H (e.g. photo, video, audio, computers, home theater, portable entertainment ) (optional) to: B&H $500.00 Gift Card Dash Sweepstakes, c/o B&H Foto & Electronics Corp., 440 Ninth Avenue, New York, NY 10001 (either option, an "Entry"). Entries must not, in the sole and absolute discretion of the Sponsor, contain obscene, provocative, defamatory, sexually explicit, or otherwise objectionable or inappropriate content. Entries deemed by Sponsor to be inappropriate will be disqualified. Entries owned by a third party, or the use of any trademarks, service marks, logos, brands, or products owned by a third party are not acceptable for entry into the Sweepstakes. Limit 1 entry per person, per day.

Winner Selection/Prizes/Odds. The B&H Social Team will randomly select a winner from among all eligible entries every Monday during the Entry Period, for a total eight (8) winners (each a "Winner"). Each Winner will receive a B&H Gift Card pre-valued in the amount of $500.00. No cash or other substitutions will be offered. Winner selection is in the sole and absolute discretion of the B&H Social Team. Any taxes are the sole responsibility of the winner. Winners will be notified and receive their prize at the email address associated with the account to which their Entry was posted or the email account provided with a mail-in entry. The odds of winning depend on the number of eligible entries received.

Identity of Winners/Eligible Participants. Winners will be identified by the email account associated with the Facebook or Twitter account from which their Entry was submitted or the email account provided with a mail-in entry. An email account holder shall mean the natural person assigned to such email account by the internet access or online service provider or other organization responsible for assigning email addresses for the domain associated with such email account. Any issues regarding the identity of a Winner shall be resolved by Sponsor in its sole discretion. The Sweepstakes is only open to residents of the United States that are at least eighteen (18) years of age on their entry date and is not open to employees of Sponsor, their immediate family, any person domiciled with such employees, or any affiliates or subsidiaries of Sponsor.

Entry Ownership/Entrant Agreements. Entrants retain full ownership and copyrights to their Submission. However, by entering the Sweepstakes entrants grant Sponsor permission to use their Entries for promotional purposes on their respective social media channels with proper credit. Entrants also agree: (a) to be bound by these Official B&H $500.00 Gift Card Dash Sweepstakes Rules; (b) that any claims related to this Sweepstakes shall be resolved individually without resort to any form of class action and that awards, shall be limited to actual out-of-pocket costs incurred in entering the Sweepstakes, and shall not include incidental or consequential damages or attorneys fees; and (c) that any actual or perceived ambiguities in these rules shall be interpreted by Sponsor in their sole discretion.

Limitation of Liability/Sponsor Modification/Cancellation Rights/ Choice of Law/ Venue/ Winners List. Sponsor is not responsible for incomplete entries or for failure to receive entries due to technical failures or human error of any kind. Winners agree that Sponsor will have no responsibility for losses or damage of any kind resulting from the acceptance, possession, or use of the prizes. Except where prohibited, participation in the Sweepstakes constitutes entrant's consent to the publication of his or her name by Sponsor in any media for commercial or promotional purposes without limitation or further compensation subject to Sponsor's respective Privacy Policies. Sponsor may modify or discontinue the Sweepstakes at any time and may disqualify from the Sweepstakes any person it determines, in its sole discretion, to have attempted to or actually tampered with or otherwise abused any aspect of the Sweepstakes. Entrants agree that in the unlikely event a dispute arises in connection with this Sweepstakes, it will be governed by the laws of the State of New York and heard exclusively in a court of applicable jurisdiction in the County and State of New York irrespective of any choice of law provisions to the contrary. To receive names of the winners by U.S. mail, please mail a self-addressed stamped envelope to: B&H Foto & Electronics Corp., Attn: B&H $500.00 Gift Card Dash Sweepstakes, 440 Ninth Avenue, New York, NY 10001. Any Winners List request must be received by B&H within one (1) year of the date the Sweepstakes is conducted.

Let us know how to reach you if you win!

Privacy 100% guaranteed; email address for contact purposes only


Already have a B&H account? Just log in tomorrow to enter again!

$0 VA Sales Tax Collected on This Item
Add to Wish List Item in Wish List

RDL SF-PA50A overview

  • 1Description

The RDL SF-PA50A is a SysFlex series 50W 70/100V mono audio amplifier designed to convert one analog input to a constant voltage amplified output for A/V technicians, system installers, and audio engineers in office buildings, retail environments, and educational facilities. Its Class-D output stage delivers 50W of RMS power at 70 or 100V from a balanced or unbalanced analog input, which offers adjustable gain via a rear-panel, single-turn potentiometer.

Connect a balanced analog source to the mono terminal block input, or utilize the unbalanced 3.5mm stereo mini jack to route signal from a mobile device. The terminal block output accommodates connection to 70 or 100V speakers, and a detachable terminal block is provided for hookup of remote control of the internal VCA. Thermal and short-circuit protection guard against electrical damage and unintended shutdown.

The SF-PA50A supports powering via the included 24 VDC external power supply and North American power cord, or from proper wiring to the terminal block power input. Engineered and manufactured in the USA, it boasts a durable metal enclosure for reliable toughness.


Converts one analog audio input to a 70 or 100V constant voltage amplified output
High-efficiency Class-D output stage produces minimal heat for all levels of expected voice or music modulation
Balanced mono terminal block input
Unbalanced 3.5mm stereo mini jack automatically 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
Supports powering via the included 24 VDC external power supply or 24V connection to the dedicated terminal block power input
LED Mute indicator glows yellow when the output is muted
Amplifier power is monitored and the current is limited to protect the power supply against shutting down, even during extreme feedback or square wave modulation conditions
Red rear-panel LED flashes when the SF-PA50A reduces power consumption to prevent shutdown of the power supply
Equipped with an internal VCA for setting the output level
Detachable terminal block provides for the connection of an external 10-kOhm potentiometer or a 0 to 10 VDC control voltage
Amplifier gain remains at maximum when the VCA input terminal is not connected
RDL remote controls are available to provide single-turn, multi-turn (rotary encoder), or button (ramp or fixed-level selection) user level control
Constructed in a durable all-metal enclosure suitable for free-standing, surface-mounted, or rack-mounted operation
Engineered and manufactured in the USA for continuous duty in demanding installations
In the Box
RDL SF-PA50A 50W 70/100V Audio Amplifier (North American Model)
  • North American Power Cord
  • 24 VDC Power Supply
  • Limited 3-Year Warranty
  • Table of Contents
    • 1Description

    RDL SF-PA50A specs

    Inputs 1 x 1/8" / 3.5 mm stereo mini jack (unbalanced)
    1 x detachable terminal block (balanced)
    Outputs 1 x terminal block for 70/100 V output
    Control 1 x detachable terminal block for VCA control
    Amplifier Class-D
    Amplifier Output 50 W RMS (70 or 100 V)
    Maximum Input Level Balanced: +25 dBu (before clipping)
    Unbalanced: +10 dBV (before clipping)
    Nominal Input Level Balanced: +4 dBu (adjustable)
    Unbalanced: -10 dBV (adjustable)
    Minimum Input Level Balanced: -10 dBu (for 20 dB below full output power)
    Unbalanced: -25 dBV (for 20 dB below full output power)
    Gain Adjustment Single-turn audio taper (with associated dual-LED VU meter calibrated to 20 dB below full output power)
    Input Impedance Balanced: > 10 kOhms
    Unbalanced: > 5 kOhms
    Common Mode Rejection > 60 dB (50 to 120 Hz)
    Frequency Response 50 Hz to 20 kHz (+0 / -3 dB)
    THD + N < 1% (1 kHz)
    Noise Below Maximum Power: < -90 dB
    Below 1/8 Power: < -80 dB
    VCA 0 to 10 VDC control via detachable terminal block (compatible with RDL VCA wall controls)
    Ambient Operating Environment 32 to 104°F / 0 to 40°C (68°F / 20°C recommended)
    Indicators Front-Panel: Power (blue), amplifier muted (yellow)
    Rear-Panel: Overload protect (red), dual-LED VU meter (two)
    Plenum Number UL 2043
    Power Requirements 24 VDC at 2700 mA via 100 to 240 VAC, 50-60 Hz, IEC C14 power supply or connection to terminal block power input
    Enclosure Material Metal
    Dimensions (W x H x D) 5.8 x 1.7 x 6.4" / 14.8 x 4.3 x 16.4 cm
    Weight 5.9 lb / 2.7 kg
    Country of Manufacture United States of America

    RDL SF-PA50A reviews

    Be the first to review this item

    RDL SF-PA50A Q&A

    RDL SF-PA50A accessories

    See any errors on this page? Let us know.