QSC RMX 1850HD (very good condition). Ex-install amplifier, been racked and well maintained. Operates perfectly with hardly any cosmetic blemishes. Great example.

230V Version

QSC Description

True Studio Quality Sound
The RMX Series amplifiers give you clean, dynamic power with the legendary QSC sound quality and reliability that pros depend on. The RMX Series deliver unmatched performance at a breakthrough price.
 
Muscular Power Plant
The power supply is the heart of an amplifier, converting raw AC power from the wall to clean DC for the audio circuitry. The RMX uses a powerful high-current toroidal transformer and ample filter capacitance to ensure generous energy reserves. This makes a critical difference in sound quality, allowing the amp to effortlessly punch out high level transients, even when driving abusive 2 ohm speaker loads.
 
Superior Performance
RMX amplifiers deliver true studio-quality sound. A full complementary output circuit using the highest-grade linear output devices delivers ultra-low distortion (<0.05% THD) and a ruler-flat frequency response. SMT (Surface Mount Technology) triples small-signal component density, enabling us to pack up to 2400 watts of power in a chassis only 2 rack spaces and less than 16" deep. And unlike other designs, RMX output devices are direct-mounted to the heat sink for optimum thermal coupling and cooling.
 
Proven Reliability:
With over 30 years of building amplifiers for the largest touring companies and venues around the world, you can count on QSC's reputation for designing the most reliable amps available.
 
Comprehensive Features:
The RMX Series is packed full of professional features that increase performance and flexibility:
The RMX 1850HD provides improved thermal performance that gives you higher continuous power in 2 ohms stereo or 4 ohms bridged applications (a RMX 1850HD exclusive!)
Independent defeatable clip limiters reduce distortion without sacrificing peak performance
Selectable low-frequency filters boost system response, protect speakers and ensure low-end tightness by more precisely matching the amplifier's range to the loudspeakers
Barrier strip, XLR and 1/4" balanced inputs plus Speakon and binding post outputs provide easy connections
Low-noise variable speed fans with rear-to-front air flow keep amplifiers and racks cool
General Features:
Compact size - up to 2400 watts in 2 rack spaces
Professional quality performance - incorporates road-proven QSC designs
High-current toroidal transformers for greater two-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
Balanced 1/4" (6.3mm) TRS, XLR and barrier strip inputs
Binding post and Neutrik Speakon outputs
Front mounted gain controls for easy access
Signal and Clip LED indicators to monitor performance
Independent DC and thermal overload protection on each channel automatically protects amplifier and speakers

Specs

Continuous Power Output Wattage
360W per channel @ 8 ohms
600W/channel @ 4 ohms
900W/channel @ 2 ohms
1150W bridged mono @ 8 ohms
1800W bridged mono @ 4 ohms

Distortion (Typical):
20 Hz-20 kHz: 10 dB below rated power Less than 0.03% THD 4 and 8 ohms
1.0 kHz and below: full rated power Less than 0.03% THD 4 and 8 ohms

Frequency Response: 20 Hz-20 kHz, +/- 1 dB, -3 dB points: 5 Hz-50 kHz

Damping Factor, 1 kHz and below: Greater than 300 at 8 ohms

Input Impedance: 10 k ohms unbalanced, 20 k ohms balanced

Input Clipping: 10 Vrms (+22 dB)

Cooling: Continuously variable-speed fan, rear-to-front air flow

Connectors, each channel:
Input: Active balanced; barrier strip, XLR and 1/4" (6.3mm) TRS tip and XLR pin 2 positive
Output: touch-proof binding posts and Neutrik Speakon

Controls:
Front: AC switch, Ch. 1 and Ch. 2 gain knobs
Rear: 10-position DIP switch

Indicators:
Power On: Green LED
Signal: Yellow LED, 1 per channel
Clip: Red LED, 1 per channel

Amplifier Protection:
Full short circuit, open circuit, thermal, ultrasonic, and RF protection
Stable into reactive or mismatched loads
Load Protection: On/off muting, AC coupling (850, 1450), triac crowbar (2450, on each channel)

Dimensions: 19 in. (48.3 cm) rack mounting, 5.25 in. (8.9 cm) tall (3 rack spaces), 15.9 in. (40 cm) deep (rack mounting to rear support ears)

Power Requirements: 230 VAC, 50-60 Hz