QSC RMX series

S

Silverburst

Member
I've been looking at a used QSC RMX2450 that is half of the new price. (It's almost the double of a used Velocity 300 I'm looking at, but I'm a little worried about it's FR-characteristics)

I did read in another thread that the GX series (might?) have a DSP that produces extra latency, cutting a little in the right "feel"-department.
So I was wondering if it would be the same in the RMX series ? can't find any info about these DSP's on either product webpages. The torodial thing that ensures extra bass response for high gain and tight rhythm stuff sounds like a good thing in the RMX line.

Anyone any experience with these amps ? (Blueser, hope you can chime in with your RMX850 ;))

And another thing about used SS amps: Can these thing really wear down ?
 
Silverburst said:
I've been looking at a used QSC RMX2450 that is half of the new price. (It's almost the double of a used Velocity 300 I'm looking at, but I'm a little worried about it's FR-characteristics)
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I've played through a wide variety of SS power amps both with my AxeFX and other preamps. Other than the differences in overall output power, I don't think anyone could tell one from another in a blind A/B test provided they were set at the same volume. Some differences could probably be measured, but not be audible.

Now, overall power does make a difference IMO, especially for clean tones with SS amps it helps having the extra headroom

I did read in another thread that the GX series (might?) have a DSP that produces extra latency, cutting a little in the right "feel"-department.
So I was wondering if it would be the same in the RMX series ? can't find any info about these DSP's on either product webpages.
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Nope, no DSP's, all analog.

The torodial thing that ensures extra bass response for high gain and tight rhythm stuff sounds like a good thing in the RMX line.
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Won't make a difference for guitar. Many PA guys say they perform better on sub duty than the newer/lighter switchmode amps - these guys prefer the "big iron" referring to the heavy transformers.

Anyone any experience with these amps ? (Blueser, hope you can chime in with your RMX850 ;))
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Yes, they're very reliable. I have used them for PA and they were a defacto standard for many years among working class bands & small sound companies. Since lightweight amps became better and more affordable, like the PLX series, many have switched and you can find bargains on the RMX line. They are heavy amps, a little over 40 lbs each IIRC.

And another thing about used SS amps: Can these thing really wear down ?
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Not really, it is possible to fry components with excessive heat from abuse but generally the protection circuits work well. Over time, capacitor values can drift and need replacing every 25 years or so.
 
Thanks a lot for this thorough elaboration tubetonez! Cleared up quite some things.

Would you think the rmx850 lacks power when it comes to headroom with it's 2x200@8Ohm ? I'd use it for home practice, and rehearsal. On stage I would certainly go direct if a PA is available and maybe use the die rmx+4x12cab as a monitor. Hoping the Greenback25+Vintage30 models will do fine when I use them in the direct signal.

There happen to also be a QSC EX-1600 (2x400@8Ohm) available from the same guy. Any experience/knowledge about these models ? Main concern is the FR and non-latancy/all analog thing. Thanks
 
It's really hard to go wrong with any QSC product. Our church is using old MX series amps and they sound good and are still kicking. I went looking for another MX1500 on ebay and found that they bring close to $320 + shipping and they are only 350 watts @ 8 ohms per channel and weigh in at 42 lbs. I started looking at the GX5 series not only for the weight savings but the power increase as well.
 
Silverburst said:
Hey Sixstring, do you have any troubles with the Class H DSP system in the GX5 ? Latency-wise...
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I haven't looked at the design details of the GX5 but class H does not require any DSP.
It works just like a class AB amplifier except that the supply rails are modulated to follow the requirements (increasing efficiency, reducing heat production).

S.R.
 
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