Members irvingklaws Posted February 18, 2011 Members Share Posted February 18, 2011 I have a pair of Ramsa WS-A500 tops running with four A550 subs. Currently powered with AB International Precedent 600 (185W/Ch@8ohms - tops) and AB Professional 9220 (590W/Ch@4Ohms - subs). Crossed via a DBX 234 @100hz instead of the proprietary active external crossover. The system is used for PA and portable jam/recording session monitor system. Electronic keys, Roland V-drums, guitar modeling pedal and multiple vocals are run through the system simultaneously. Also use it for monitoring when recording/multitracking. I really love the sound of the Ramsa's. However I'd like to replace the back-breaking heavy amps, which are perhaps somewhat under powered for the speakers. I'm considering QSC PLX, Crown XTi/XLS, even Behringer and Peaveys. Can anyone comment from experience on the comparative differences in these amps sound quality-wise? I've looked at lots of threads on other boards and opinions seem mixed, and sometimes uninformed. While I'd really like to lighten the load, I'd hate to go to all the trouble and find it just doesn't sound as good. I'm also not sure how much wattage I should get to properly power the system to it's full potential. Should I get as close to the exact wattage or do I need to factor in some overage for headroom? If so how much? The speakers are older so not sure if there will be any issues I need to account for with these newer amp designs. I only know enough to know wattage and specs don't tell all. Thanks in advance for your comments. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 18, 2011 Members Share Posted February 18, 2011 Easiest and most reasonable solution is to get QSC GX-5's, one for the left and one for the right, use the on-board crossovers, and it's simple as hell and about 1/2 the weight in watts per pound compared with what you are carrying right now and 2 rackspace. Nothing wrong with the sound quality, plus you get a good limiter on the GX, your AB-600 doesn't have a limiter, your 9220 does (IIRC). That's as much power as I would recommend with the speakers and you will want to be careful at that. A GX-3 would be very close power-wise to what you have right now, and even lighter. There is a pretty good used market for AB depending on where you live. The 600 is a solid commodity workhorse where size and weight is not important. The 9220 is a step up. Link to comment Share on other sites More sharing options...
Members Unalaska Posted February 19, 2011 Members Share Posted February 19, 2011 I'd say 1 GX5 for mono biamp or 1 gx3 and 1 gx5. Peavey IPR1600 would be good too, or that and an IPR3000. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 19, 2011 Members Share Posted February 19, 2011 I'd say 1 GX5 for mono biamp or 1 gx3 and 1 gx5. Peavey IPR1600 would be good too, or that and an IPR3000. I thought about 1 x GX-5 but it won't run the 2 ohm load that 4 subs would cause. That's why, with 2 amps I would stay with biamped internal to the amp for simplicity sake. Link to comment Share on other sites More sharing options...
Members Unalaska Posted February 19, 2011 Members Share Posted February 19, 2011 didn't know the a550's were 4 ohm. Link to comment Share on other sites More sharing options...
Members irvingklaws Posted February 19, 2011 Author Members Share Posted February 19, 2011 The A550's are 8ohms and 400W each. Right now I run them parallel 2 per side. If I ran the all 4 bridged mono they'd need to be at either 8 or 2 Ohms. I'd prefer not to run anything lower than 4 Ohms. The GX5 isn't as light as I'd hoped but I've been reading up on them. A GX7 looks like it could run the subs 2 per channel and it's over 10lbs lighter. But it's doesn't look like the internal crossover's on the GX work on both channels(?), so I'd need an external. If I'm going that route then a combination of QSC PLX2's (1104 and 1804) would provide similar power and are much lighter still. The newer Crown XLS drivecores are crazy light, have built-in crossovers and limiting. It looks to me like an XLS1500 would work on the tops. However the XLS2500 appears a little shy in power for the subs. Then there's the Behringer and Peavey IPR that I know little about. I also don't know if there are any significant sound quality differences in these amps. Link to comment Share on other sites More sharing options...
Members dennis a Posted February 19, 2011 Members Share Posted February 19, 2011 But it's doesn't look like the internal crossover's on the GX work on both channels(?) How can the internal xover do biamp without working on both channels? Link to comment Share on other sites More sharing options...
Members DaBender Posted February 19, 2011 Members Share Posted February 19, 2011 If you engage the xover on the GX series amps you get highs on one channel and lows on the other. The Peavey IPRS are independently switchable, rated for 2 ohms, are bridgeable and are much lighter. Several folks on the Peavey forum have been raving about them for a while now. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 19, 2011 Members Share Posted February 19, 2011 This is why I suggested the GX-5 which would allow 2 subs and a top on each amp. 2 ohms on an amp (a quality amp) that's designed for 2 ohms is not a problem. Your 9220 is one such amp, it's identical (internally) to the Precident 900A with the internal fan kit is rated for 2 ohms and will indeed do this reliably. (I had some engineering involvement with them before they changed ownership ~15 years ago). Here is the owner's manual for your reference: http://www.abamps.com/pdfs/900a-1100a-9220a-9420a-man.pdf A PLX-XX02 series would be another option, again, nothing wrong with 2 ohms on these either. I have dozens of the original PLX opertating at 2 ohms and have had no failures in almost 15 years. Incidently, they replaced racks of AB 1100A's and 900A's with a weight savings of probably 1000 lbs. Link to comment Share on other sites More sharing options...
Members irvingklaws Posted February 20, 2011 Author Members Share Posted February 20, 2011 ...2 ohms on an amp (a quality amp) that's designed for 2 ohms is not a problem. Your 9220 is one such amp, it's identical (internally) to the Precident 900A with the internal fan kit is rated for 2 ohms and will indeed do this reliably. A PLX-XX02 series would be another option, again, nothing wrong with 2 ohms on these either. I have dozens of the original PLX opertating at 2 ohms and have had no failures in almost 15 years. ... I'd only need to run subs at 2 Ohms if I had all four hooked in parallel with the amp in bridged mono mode. The tech manuals for both the aforementioned amps only list 4 and 8 ohm operation for bridged mono. 2 Ohm operation is only possible in stereo mode, which wouldn't be necessary for my setup...unless I'm missing something? That's one reason I mentioned the PLX-xx04 series which are lighter and cheaper than the xx02. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 20, 2011 Members Share Posted February 20, 2011 I'd only need to run subs at 2 Ohms if I had all four hooked in parallel with the amp in bridged mono mode. The tech manuals for both the aforementioned amps only list 4 and 8 ohm operation for bridged mono. 2 Ohm operation is only possible in stereo mode, which wouldn't be necessary for my setup...unless I'm missing something? That's one reason I mentioned the PLX-xx04 series which are lighter and cheaper than the xx02. No, no, no. Forget bridge mode. You have no need or use for bridge mode. That has nothing to do with this discussion. Don't know where it even came from. The PLX-3602 is PLENTY of power for 4 of your subs off of one channel in stereo mode. Your speakers are not very robust and I would not trecommend popwering your subs at greater than 400 watts per box. I have reconed plenty of them, and FYI parts are very difficult to get and getting harder and more expensive all the time. In fact a 3102 would be plenty big. Link to comment Share on other sites More sharing options...
Members irvingklaws Posted February 20, 2011 Author Members Share Posted February 20, 2011 First of all, thank you for your input and taking time to respond to this thread. To be clear, I wasn't suggesting bridging. I just didn't understand that you were suggesting I only use one side of the amp. I know how difficult parts are to find for these speakers. That's why I'm soliciting advice on how best to power them to their potential (both power AND sound quality-wise) without risking harm to them. Also to clarify, I'm NOT suggesting alternatives to using GX5's because I want more power. Only because I'd like less weight and the correct amount of power to SAFELY use the speakers I have, without a loss in sound quality (compared to the AB amps)...if that's possible. But, a 3102 or 3602 doesn't make sense to me if I'm only to use one channel at 2 ohms. Whats the other channel for? I have read that overage or headroom should be factored when choosing an amp. QSC's website states that most manufacturers recommend powering them with, "...two times (2 x) the Continuous (RMS) Power rating." This again is why I asked for advice. The unique one-amp-per-side configuration of the GX aside, I need one amp for the subs and another for the tops. However, if what you say is true then an amp pushing 800W (perhaps a little less?) at 4 ohms per channel like an 1804, XLS2500, or perhaps IP3000 seem like logical choices for use on my subs. Sorry for the longish post. I'm just trying to be clear and I want the best for my speakers. If there's something you think I'm missing, or some other thread I should read, please feel free to point it out. Thanks again. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 20, 2011 Members Share Posted February 20, 2011 One channel for subs and one channel for tops. One amp for everything, if mono is acceptable. Otherwise you would need 2 amps. Link to comment Share on other sites More sharing options...
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