QSC RMX 2450a Power Amplifier
Part of QSC's workhorse RMX series of amplifiers, the 2450a offers ultra-low distortion in a cool-running design, powering 750 watts per channel at 4 ohms.
$1,049.99
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QSC RMX 1850HD Power Amplifier
No longer available at zZounds
An update to QSC's long-running RMX series, RMX HD power amps deliver incredibly low distortion and higher continuous power thanks to improved thermal specs.
Overview
QSC's RMX series amplifiers give you clean, dynamic power with legendary QSC sound quality and reliability that pros depend on. QSC combined their rugged, high-output designs with the finest circuit technology to deliver unmatched performance at a breakthrough price. RMX amps have balanced XLR and 1/4" TRS inputs. Outputs include binding posts and Neutrik Speakon connections. These stereo power amps are only 2 rack spaces tall and 15.9 in. deep. Other features include ultra low distortion (.05% THD), a low-noise variable speed fan with rear-to-front air flow to keep your amplifier and racks cool, and selectable low-frequency filters to protect your speakers and increase headroom. QSC power amps are backed by a 3-year transferable warranty.
- 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 in. 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.
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) & a ruler-flat frequency response. SMT (Surface Mount Technology) triples small-signal component density, enabling them to pack up to 2400 watts of power in a chassis only 2 rack spaces & less than 16" deep. And unlike other designs, RMX output devices are direct-mounted to the heat sink for optimum thermal coupling & cooling.Features:
- 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 in. 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.
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: 100, 120, 230 VAC, 50-60 Hz
Note: Register your new product online with QSC and receive a Free 6-Year Extended Warranty upgrade (a $99 value).
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: 100, 120, 230 VAC, 50-60 Hz
Note: Register your new product online with QSC and receive a Free 6-Year Extended Warranty upgrade (a $99 value).
Documents and Manuals
For support or warranty questions, please contact the manufacturer:
Phone: 800-772-2834
Web: http://qsc.com/support
Phone: 800-772-2834
Web: http://qsc.com/support
Reviews
Reviewers gave this product an overall rating of 5 out of 5 stars.
(27 ratings)
Submitted February 2, 2007 by a customer from bitcore.org
QSC RMX 1850 HD Power Amp Customer Review
Verified Customer
zZounds has verified that this reviewer made a purchase from us.
I'm TOTALLY SOLD on the QSC rmx line - I want to try the PLX amps, but can't quite afford them, and I don't need a new amp as of yet. If I need some clean juice without any whizzbang crap, the RMX is what I'd go for. The PLX, PLX2, and Powerlight series seem to be pretty bad ass too. RMX is the budget line, but you don't get screwed with cheap components because the manufacturer thinks your cheap - Quality beef. Get it. Get it now, and don't feel afraid that it will crap out on you in the middle of a performance - just try not to overpower and cook your speakers, the RMX will do it! just keep those gain knobs in check!
Sound
I love this amp, very clean, doesn't distort the audio, and MAN is it powerful. I've tried to get it to sound bad and distort the audio signal, but I just can't do it. Drive it with a computer where you can't overdrive the input voltage on the amp, and you can't go wrong. I haven't driven the amps I own with a mixer that's outputting an overly hot signal, so I don't know how that will sound - but you shouldn't ever do that in the first place.
Features
It has a 30hz, 50hz rolloff filter, clip limiters, parallel/stereo inputs, and line out on ch2 so you can chain amps in bridge mode... Nothing more, nothing less. Speakon, and bannan\terminals for outputs, couldn't be happier with that combo. It's an amp, not an EQ, not a crossover - it does what you want it to do. It would be nice to have a basic… read more high/low variable crossover, but if you want that, you need to go to the PLX line.
Ease of Use
Quite simple. Dip switch in the rear controls the bridge/crossover/etc, so if you need to change that often, you'll have to get behind it which means you'll have to unmount it from a rack, but to change cables and such you'd need to do that anyways.
Quality
I've had my RMX 1850HD for about 2.5 years, it's been solid as a rock. I got an RMX 2450 last summer and it's even more amazing. I love these! I can't tell you how rugged these are. You can turn them all the way up, and if the ohm load of the speakers doesn't dip too low, they won't clip. Especially the HD models. I've put some seriously abusive loads on the 1850HD before, STUPID wiring, frankly. For example, an accidental 1 ohm bridged load for a week and it hummed along fine-> it would only clip if I pushed it past 3/4 of full gain in that condition (which was *way* over the sub's power limit anyways, I couldn't push the driver that hard anyways). It's never went into thermal protection mode, and still works wonderfully with mismatched loads in each channel. I've killed 4 speakers with this amp too, *not* from clipping, but from sheer overpowering the drivers! 1 & 2: A cheap set of 3-ways: successively melted the voice coils in each driver with 1/2 of the amp's gain (65W speakers with 350W of headroom, deep, bassy music killed them quick). Speaker 3: adire audio 15" tumult, MK1. First I blew the driver mechanically from over excursion, had it reconed, and then melted the voice coil in a sealed box, wired to 4 ohms with the amp bridged - 1600W of headroom. Speaker 4: $5, 50W sub, decided to pump all the power I could through it to blow it up - and my god did it blow up. On top of those abusive loads I've made it push, one day I wasn't paying attention and was using wires hooked to the terminals instead of speakon and I was switching wires around on the sub. Like a complete fool, I forgot to shut the amp off - AND it was bridged. Inevitably, I accidentally dead shorted the wires for a few seconds. The wires arced in a DC fashion, the clip lights lit up, I panicked and slammed the switch off as soon as I could. I nervously finished wiring up the sub, flipped it back on, and much to my relief, the amp has been pumping - just as it always has - for a year and a half after that.
Value
I don't feel that I should rate value as a 10, because you can get better power:dollar with older/cheaper amps, but I'm so sold on the durability, reliability, and predictability of these amps that I wouldn't want to get any other brand. I'm really quite serious - Maybe crown, but their stuff is ludicrously expensive... Man I hope I don't sound like I work for QSC or own stock in them... hmmm, stock's actually not a bad idea...
Manufacturer Support
I have not had to deal with the company, I have not had any problems or questions, but their website is VERY informative and they make their telephone, address, and e-mail for tech support very obvious and easy to get to. There's a ton of tech data about each amp they make and some very interesting other stuff... for example, did you know that if you ran a 1khz sine wave through the RMX 1850HD hooked to a 2 ohm load on both channels, the amp will put out 4608 BTU/hour? What other amplifier manufacturer lists that data? ...Or even TESTS that? I'm quite sure that if I had a service problem, that I would be extremely pleased.
The Wow Factor
Ok, I'm sure lots of people don't think this amp has much sex appeal or any "ouuuh, ahhh" factor at all, but I like it. It's clean, It's black, it's SIMPLE, and if there's a problem - the clip light is very easy to spot and you won't be distracted by any other crap like LCD screens.
Musical Background:
DJ, PA, hobby, personal use, home theater
Musical Style:
I run near everything through this amp, electronic, Drum and bass, hip-hop, action movies - everything sound read less
Sound
I love this amp, very clean, doesn't distort the audio, and MAN is it powerful. I've tried to get it to sound bad and distort the audio signal, but I just can't do it. Drive it with a computer where you can't overdrive the input voltage on the amp, and you can't go wrong. I haven't driven the amps I own with a mixer that's outputting an overly hot signal, so I don't know how that will sound - but you shouldn't ever do that in the first place.
Features
It has a 30hz, 50hz rolloff filter, clip limiters, parallel/stereo inputs, and line out on ch2 so you can chain amps in bridge mode... Nothing more, nothing less. Speakon, and bannan\terminals for outputs, couldn't be happier with that combo. It's an amp, not an EQ, not a crossover - it does what you want it to do. It would be nice to have a basic… read more high/low variable crossover, but if you want that, you need to go to the PLX line.
Ease of Use
Quite simple. Dip switch in the rear controls the bridge/crossover/etc, so if you need to change that often, you'll have to get behind it which means you'll have to unmount it from a rack, but to change cables and such you'd need to do that anyways.
Quality
I've had my RMX 1850HD for about 2.5 years, it's been solid as a rock. I got an RMX 2450 last summer and it's even more amazing. I love these! I can't tell you how rugged these are. You can turn them all the way up, and if the ohm load of the speakers doesn't dip too low, they won't clip. Especially the HD models. I've put some seriously abusive loads on the 1850HD before, STUPID wiring, frankly. For example, an accidental 1 ohm bridged load for a week and it hummed along fine-> it would only clip if I pushed it past 3/4 of full gain in that condition (which was *way* over the sub's power limit anyways, I couldn't push the driver that hard anyways). It's never went into thermal protection mode, and still works wonderfully with mismatched loads in each channel. I've killed 4 speakers with this amp too, *not* from clipping, but from sheer overpowering the drivers! 1 & 2: A cheap set of 3-ways: successively melted the voice coils in each driver with 1/2 of the amp's gain (65W speakers with 350W of headroom, deep, bassy music killed them quick). Speaker 3: adire audio 15" tumult, MK1. First I blew the driver mechanically from over excursion, had it reconed, and then melted the voice coil in a sealed box, wired to 4 ohms with the amp bridged - 1600W of headroom. Speaker 4: $5, 50W sub, decided to pump all the power I could through it to blow it up - and my god did it blow up. On top of those abusive loads I've made it push, one day I wasn't paying attention and was using wires hooked to the terminals instead of speakon and I was switching wires around on the sub. Like a complete fool, I forgot to shut the amp off - AND it was bridged. Inevitably, I accidentally dead shorted the wires for a few seconds. The wires arced in a DC fashion, the clip lights lit up, I panicked and slammed the switch off as soon as I could. I nervously finished wiring up the sub, flipped it back on, and much to my relief, the amp has been pumping - just as it always has - for a year and a half after that.
Value
I don't feel that I should rate value as a 10, because you can get better power:dollar with older/cheaper amps, but I'm so sold on the durability, reliability, and predictability of these amps that I wouldn't want to get any other brand. I'm really quite serious - Maybe crown, but their stuff is ludicrously expensive... Man I hope I don't sound like I work for QSC or own stock in them... hmmm, stock's actually not a bad idea...
Manufacturer Support
I have not had to deal with the company, I have not had any problems or questions, but their website is VERY informative and they make their telephone, address, and e-mail for tech support very obvious and easy to get to. There's a ton of tech data about each amp they make and some very interesting other stuff... for example, did you know that if you ran a 1khz sine wave through the RMX 1850HD hooked to a 2 ohm load on both channels, the amp will put out 4608 BTU/hour? What other amplifier manufacturer lists that data? ...Or even TESTS that? I'm quite sure that if I had a service problem, that I would be extremely pleased.
The Wow Factor
Ok, I'm sure lots of people don't think this amp has much sex appeal or any "ouuuh, ahhh" factor at all, but I like it. It's clean, It's black, it's SIMPLE, and if there's a problem - the clip light is very easy to spot and you won't be distracted by any other crap like LCD screens.
Musical Background:
DJ, PA, hobby, personal use, home theater
Musical Style:
I run near everything through this amp, electronic, Drum and bass, hip-hop, action movies - everything sound read less
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