QSC RMX 1850HD Power Amplifier

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.

Overall User Ratings (based on 27 ratings)
  • Overall:
    5 out of 5 stars
  • Sound:
    5 out of 5 stars
  • Features:
    4 out of 5 stars
  • Ease of Use:
    5 out of 5 stars
  • Quality:
    5 out of 5 stars
  • Value:
    5 out of 5 stars
  • Manufacturer Support:
    5 out of 5 stars
  • The Wow Factor:
    3.5 out of 5 stars
Overall: 5 out of 5 stars
(27) (see rating details)
Submitted February 2, 2007 by a customer from bitcore.org

QSC RMX 1850 HD Power Amp Customer Review

Overall: 5 out of 5 stars
(see rating details)
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 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
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