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Everything In Music Since 1958
Everything In Music Since 1958

QSC RMX4050a Power Amplifier - Mint, Open Box

Original price $2,148.79
Original price $2,148.79 - Original price $2,148.79
Original price $2,148.79
Current price $1,449.00
$1,449.00 - $1,449.00
Current price $1,449.00
♫ In stock
About Inventory Status

Call or text us at 301-946-8808.

In stock: It is in stock and available to ship or pickup. Apparel must be shipped from another location and is not available for in-store pickup. We can usually ship or have these items available for pickup by the next business day if they don't require inspection, special handling, or setup. Our pickup location is 11151 Veirs Mill Rd. Silver Spring, MD 20902.

📆 Preorder: It is on the way to our warehouse. We can't predict when preorder items will arrive due to current supply chain issues. If you place an order for one of these items someone will contact you to estimate the delivery date.

Out of stock: We don't currently have it available but you're not out of luck yet. We still may be able to get it. If you order one of these items we will contact you with an estimated fulfillment date. You have the option to cancel the order if you change your mind.

Special order: The item is so special that it needs to be custom ordered for you. Some of these items are works of art and have to be made individually. Orders for special order items must be prepaid and we cannot accept cancellations or refunds.

█ Sold out: We don't think we can get this item because it was either discontinued by the manufacturer or was limited in quantity. If you want or need this item call or text us. Sometimes we can help you track down the item through other sources or help you find something similar.

About Item Conditions

Call or text us at 301-946-8808.

New: The item is brand new as received from the manufacturer with a full manufacturer warranty. Instruments such as guitars, snare drums, drum kits, brass and woodwind instruments may be opened for photography and quality control inspection and may not be in a factory sealed box.

Mint or Open Box: The item may have been opened and tested but has been repackaged. The original packaging may have superficial issues but the item itself and any originally included accessories are in perfect, like new condition.

Display Model: These items are so cool that we put them on display in our legendary shop. The condition is brand new as received from the manufacturer with manufacturer warranty. Rest assured, these items undergo a very careful inspection before shipping.

Demo: These items have been on our sales floor for demo purposes and will likely show signs of use. The original packaging may no longer be included, but you can be assured that you are receiving an awesome item and an awesome price.

Used: The item is used. These item may have varying degrees of wear. Please read the description for information about the condition of the item. Used items do not carry a warranty.

B or C Stock: Factory refurbished. These items were purchased from the manufacturer in a refurbished condition. They will show some cosmetic issues, but nothing that would impact performance. Being that these are sealed from the manufacturer, we generally do not open these to photograph the cosmetic issues. They are guaranteed to work and may have a limited warranty or you may purchase an extended warranty in some cases. Please see the listing description for item specific information.

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Quality Audio - The QSC RMX4050a Power Amplifier

The QSC RMX4050a is a compact power amplifier.

  • Compact size — up to 2500 watts in two rack spaces, or 5000 watts in three rack spaces
  • High-current toroidal transformers, for greater 2-ohm power and low noise
  • Independent user-defeatable clip limiters reduce distortion
  • Selectable low-frequency filters (30 Hz or 50 Hz) protect speakers and increase headroom
  • The 4000-watt RMX4050a operates on a standard 15 amp plug (120V)
  • Both the RMX4050a and the RMX5050a feature a dual mono, high-current power supply for increased reliability and performance
  • Balanced 1/4-inch (6.3 mm) TRS, XLR, and barrier strip inputs
  • Touch-proof binding post and Neutrik Speakon outputs
  • Front mounted gain controls for easy access
  • Signal and clip LED indicators for monitoring performance
  • Independent DC and thermal overload protection on each channel automatically protects amplifier and speakers
  • 3-year warranty plus optional 3-year extended service contract


Power per Channel, Stereo Mode (both channels driven)

  • 8Ω, FTC 20 Hz–20 kHz, 0.1% THD: 800 (650**) W
  • 8Ω, EIA 1 kHz, 0.1% THD: 850 W
  • 4Ω, FTC 20 Hz–20 kHz, 0.1% THD: 1300 W
  • 4Ω, EIA 1 kHz, 0.1% THD: 1400 W
  • 2Ω, FTC 20 Hz–20 kHz, 1% THD: 1600 W
  • 2Ω, EIA 1 kHz, 1% THD: 2000 W

Power, Bridge-Mono Mode

  • 8Ω, FTC 20 Hz–20 kHz, 0.1% THD: 2600 W
  • 8Ω, EIA 1 kHz, 0.1% THD: 2800 W


  • Signal-to-Noise: -100 dB
  • Input Sensitivity: 1.23V, (+4.0 dBu)
  • Voltage Gain: 50x (34 dB)
  • Output Circuit: 2-tier Class H
  • Frequency Response: 20 Hz–20 kHz: +0/-1 dB -3 dB points: 5 Hz and 50 kHz (LF filter bybassed, 8Ω)
  • Damping Factor (1 kHz and below): > 300 at 8Ω, > 250 at 8Ω
  • Input Impedance: 10 kΩ unbalanced; 20 kΩ balanced
  • Input Stage Clipping: 10 V rms (+22 dBu), 6.4 V rms (+18 dBu)
  • Cooling: Continuously variable speed fan, back-to-front air flow
  • Connectors (each channel): Input: Active balanced; 3-pin Euro-style detachable terminal block and XLR (pin 2+)
  • Output: Touch-proof binding posts; Neutrik Speakon
  • Controls: Front: AC switch; Channel 1 & 2 gain knobs
  • Rear: 10-position DIP switch
  • LED Indicators: Power on: Green; Signal: Yellow (1 per channel); Clip/Protect: Red (1 per channel)
  • Amplifier Protection: Full short circuit, open circuit, tdermal, ultrasonic, RF protection. Stable into reactive or mismatched loads
  • Load Protection: Turn-on/off muting; AC coupling (850, 1450); Triac crowbar (1850HD, 2450, 4050HD, 5050) on each channel
  • Dimensions: 132 (3 RU) × 482 × 404 mm (5.25 (3 RU) × 19 × 15.9 inches)
  • Weight: 30.8 kg (68 lbs.)

Manufacturer: QSC Audio
Model: RMX4050A
SKU: I140928-GA202399-3-WHXE
UPC: 684284062864

We are Chuck Levin's Washington Music Center

Maryland, Virginia, and Washington DC's legendary music shop. Family-owned and operated since 1958. Buy gear the way it was meant to be bought, from a store that's been there through it all and has the vibe to prove it. We're staffed with musicians and industry experts, people that live and breathe music gear. Our mission is to help you find the right gear for your project, that thing that will bring you the most joy out of what you do. We're an authorized dealer for almost every brand, we stock items the other stores don't, so you can try before you buy. Stop by our Wheaton, MD showroom and see for yourself.

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