Clip limiting: qsc ex4000 vs qsc Rmx 5050

C

Conrad Muzoora

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Feb 15, 2014
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Uganda
www.kooleventug.com
I have been running my subs (ev qrx 218) on a Rmx 5050 for about 2 years, one sub per channel. Recently I acquired a 22year old ex 4000 to run my "B" rig same subs. Now I kind of like to extract every last bit of output from my amps (about 1/3 power as described by qsc) and to be honest, the ex 4000 sounds cleaner and equally loud in reasonable clip than the 5050. Makes me wonder, is the diff due to better components in the made in USA ex or just better clip limiting in the ex?
Conrad
www.kooleventug.com


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Re: Clip limiting: qsc ex4000 vs qsc Rmx 5050

I could be wrong, but I don't believe the EX-4000 has clip limiters.
I'll check the owners manuel, and get back to you.
and Yes, they are awsome sounding amps. I still have 2 in use.
Heavy as shit, but I'm not replacing them until one of them dies.
Don't forget, when they were introduced, they were QSC top-of-the-line series.
 
Re: Clip limiting: qsc ex4000 vs qsc Rmx 5050

Nothing wrong . The 5050 is running my "A" rig and I was wondering if I should switch it to "B" rig. Still not sure if the ex4000 will hold out in mission critical situations since it's more than legal drinking age!!!
Conrad


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Clip limiting: qsc ex4000 vs qsc Rmx 5050

Hi all,
I mostly play recorded sound so I make sure I run my subs on amps that are matched to the Rms rating. My subs are ev Qrx 218 one on each side of either Rmx 5050, ex4000, jbl mpa1100 or Rmx 4050 depending on the rig. To get the most out of them, some clip lights come on, not continuously ofcource. And I don't let them distort. When I do live sound, I only add more boxes and amps to get the desired spl and headroom.
Conrad


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Last edited:
Re: Clip limiting: qsc ex4000 vs qsc Rmx 5050

Conrad Muzoora said:
Hi all,
I mostly play recorded sound so I make sure I run my subs on amps that are matched to the Rms rating. My subs are ev Qrx 218 one on each side of either Rmx 5050, ex4000, jbl mpa1100 or Rmx 4040 depending on the rig. To get the most out of them, some clip lights come on, not continuously ofcource. And I don't let them distort. When I do live sound, I only add more boxes and amps to get the desired spl and headroom.
Conrad


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Click to expand...

When you see clip lights, you are getting distortion. Clip lights should never come on during normal operation. If they do, you have failed in bringing enough rig.
 
Re: Clip limiting: qsc ex4000 vs qsc Rmx 5050

Brian jojade said:
When you see clip lights, you are getting distortion. Clip lights should never come on during normal operation. If they do, you have failed in bringing enough rig.
Click to expand...
One thing that many people don't "get"-is what the term distortion means.

They think that a "clip eliminator" gets rid of or reduces "distortion". Well it can help from keeping the amp from producing square waves and all the extra harmonic content that comes with that.

HOWEVER distortion means ANYTHING that is "distorting" the waveform or making it take on a shape that is not what it was when it went in.

So by limiting or squashing the dynamic range, they are distorting the signal. WHETHER or not they hear the extra harmonic distortion.;

How much does this matter-it depends. Some hate it and some like it and some don't care. There is no simple easy answer.
 
Clip limiting: qsc ex4000 vs qsc Rmx 5050

What I care about is nasty audible distortion! It's always a trade off. Either get a big expensive amp or a cheap smaller one that can get you the results you need without audible distortion
Conrad


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Re: Clip limiting: qsc ex4000 vs qsc Rmx 5050

Conrad Muzoora said:
What I care about is nasty audible distortion! It's always a trade off. Either get a big expensive amp or a cheap smaller one that can get you the results you need without audible distortion
Conrad


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Click to expand...
How do you get the same results out of a cheap amp?
 
Re: Clip limiting: qsc ex4000 vs qsc Rmx 5050

The EX4000 clip limiter is a little primitive, being based on an optocoupler shunt in the input stage with the LED being driven from the same line that lights up the front panel clip LED.

The RMX5050 clip limiter is based on an OTA in the negative feedback loop of the input op amp. The OTA acts like a variable resistance: normally very high, but decreasing when IABC from the loss-of-feedback detection circuitry increases. The attack and release are are little slower.

Regarding clipping and distortion: any clipping is distortion. A clip limiter does not prevent clipping but will reduce audible distortion when clipping occurs. If you rely too heavily on clip limiting to make up for inadequate headroom, you're liable to inhibit dynamics by squashing the peaks. Very brief and infrequent clips tend to be inaudible. And keep in mind that some amps' clip LEDs are very sensitive to brightly indicating even the shortest and most insignificant little bits of clipping, and well, some aren't. :?~:-?~:???:
 
Re: Clip limiting: qsc ex4000 vs qsc Rmx 5050

Thanks Bob for chiming in. Qscaudio has served me well, these amps continue to amaze me by their rock solid reliability. The Rmx in quote is a 2006 model, 8 years down the road and I guess not yet broken in. The ex is approx 22 years and I still swear by it. God bless QSC!
Conrad


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