Subwoofer amp: 2 plates or a professional 2 channel unit

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I'm going to use two subs. Now, I could go with two plate amps built in each sub, or I could use an external, professional 2 channel amp. I noticed that there's a ton of used professional 2 ch amps, notably by QSC, that sell on ebay for not much money. Those were used for PA's and such. I don't need much in terms of controls as I'm going to use external Richter scale equalizer. So, question for folks with experience - which is better?
 
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Having two separate amps is better in terms of "fail safe" operation.
QSC makes some good amps and some amps that don't perform well for sub use, plate amps go from crap to very good examples like those from SpeakerPower. Brian Oppegaard, president of SpeakerPower spent 11 years as Director of Engineering at QSC Audio Products.
 
Having two separate amps is better in terms of "fail safe" operation.
QSC makes some good amps and some amps that don't perform well for sub use, plate amps go from crap to very good examples like those from SpeakerPower. Brian Oppegaard, president of SpeakerPower spent 11 years as Director of Engineering at QSC Audio Products.

In the past, I used Dayton Audio plate amps with good results. But now that I got the Richter scale, I don't need all the controls and equalization. Plus Daytons rarely come used and the new ones cost about $265 a pop. QSC's looked pretty good and simple so I'm tempted... Speaking of good vs amps that don't perform well, which QSC model would you recommend for home subwoofer application?
 
That's a problem specific to the RMX line. So far as I know, none of their other amps suffer from the same problem.

I use a QSC USA-850 for my home stereo, which is an install amp, class AB with 425w/ch@4ohm, will drive 2ohm for slightly more power, or 8ohm for half the 4ohm rating. Bridgable for more voltage swing.
Fan isn't particularly loud, but can go into hairdryer mode if you bridge it into a low impedance and then hammer away for a while.


I'd consider either an old Crown/Crest/QSC amp, or one of Behringer's iNuke amps if you're willing to change the fan - there's a lot of cheap power there.

Chris
 
One thing to consider is the noise from the QSCs cooling fans. I use 4 QSC RMX series amps and they are far too loud to have in the listening room. (Also if you consider used amps check the gain pots haven't gone scratchy - all of mine have)

What about replacing noisy fans with quiet computer grade ones? And I would remove all gain pots altogether - just the power! All controls would be effected from Richter scale.
 
You really want to keep the gain pots. RMX amps do very well on resale. Removing the pots will give the amp exactly two settings: off, or full-power. Useless for troubleshooting things or if you ever want to connect another source, and will also kill the resale value almost entirely.

You can replace the fan quite comfortably without any problem. Just check operating voltages - it might be a 24v fan.

Chris
 
You really want to keep the gain pots. RMX amps do very well on resale. Removing the pots will give the amp exactly two settings: off, or full-power. Useless for troubleshooting things or if you ever want to connect another source, and will also kill the resale value almost entirely.

You can replace the fan quite comfortably without any problem. Just check operating voltages - it might be a 24v fan.

Chris

What you said about the gain pots makes good sense. After all I can always have them all the way up. Thanks.
 
That's a problem specific to the RMX line. So far as I know, none of their other amps suffer from the same problem.

I use a QSC USA-850 for my home stereo, which is an install amp, class AB with 425w/ch@4ohm, will drive 2ohm for slightly more power, or 8ohm for half the 4ohm rating. Bridgable for more voltage swing.
Fan isn't particularly loud, but can go into hairdryer mode if you bridge it into a low impedance and then hammer away for a while.


I'd consider either an old Crown/Crest/QSC amp, or one of Behringer's iNuke amps if you're willing to change the fan - there's a lot of cheap power there.

Chris

Thanks again. I just saw fully refurbished QSC USA-900 being offered on ebay for 99.99 right here in so. Cal. Maybe it's my lucky day...
 
I acquired a Crown XLS1500 2nd hand for a mate and it's excellent. Very very quiet for the new class D amps at only 4kg and drives his 15in Jonah Lomu sub in a 3cuft ported box easily in his HT setup without needing a bump box! It also has RCA inputs and your normal screw down speaker terminals unlike allot of pro amps. It does have basic digital XO settings via an lcd screen but a MiniDSP 2x4 takes care of that. He did need a hum destroyer though like majority of commercial to pro setups but the hum wasn't overly loud unlike my system was with any pro amp (currently use the FP14000 Clone amp but have an EP4000 and iNuke NU4-6000) and I only recommend the Jensen Sub-1RR for Sub hum destroyong as this was the only product that totally rid my system and others here in Australia of all hum unless your system is all balanced... The Sub1 is expensive though but so worth the dollars after trying everything and failing to eliminate it!
 
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