QSC GX series

[LowPhreak]

Has anyone used them? Any comparisons on their sound? I'm looking for a decent sounding 'budget' amp to drive some SR4725X's, and the GX3 (300wpc-8 ohms) would be enough for the levels they'll be used at.

[boputnam]

I don't personally know that line, but have used many of their others, for decades - in-particular the CX-series, which lack the fancy connections (saving me money) and have performed without ANY issues for +10-years.

I can vouch for the brand - if QSC is marketing it, it is good. As you know, those are lower wattage units - they seem perfect for your application.

Alternatively, I'll bet you could find some used CX on eBay in your target wattage.

[LowPhreak]

Thanks for the reply, bo.

I've seen some threads in the past where you've always had high praise for the QSC's. I'm just looking for a less expensive alternative on this go round. I don't expect say, Audio Research/Krell/Levinson performance sonically that I'm used to, but something "listenable" at least.

Looks like they've saved some $$ on this line by nixing 2 ohm ability and bridging, both of which is fine with me for this rig. If I ended up liking it, I can always get another and vertical bi-amp, and/or later do a bridging QSC if I ever get that 4645C I've wanted. (Though there aren't a lot of amps I'm a huge fan of in bridged mode. Maybe you have some suggestions on various QSC models there too?)

I might look at used, but I'd rather buy higher-end home audio that way than pro audio. I would think pro gear is more prone to abuse.

[LowPhreak]

Well, I'm going to a local shop to pick up a GX3 today. The best way to find out is put it through the paces myself, eh?

I'll try to post here soon with some impressions.

[LowPhreak]

I'll post here what I posted on another forum, slightly edited:

"The past several days I've been auditioning a GX3 against a PLX1104 on my rig at home - a fair comparison since both are approx. 300 wpc/8 ohms. No signal processing except an analog ART XL231 EQ...so source > preamp > EQ > amp, then full-range to a pair of JBL SR4725X's @ 8 ohms. Both amps levels matched as close as possible using test CD's + SPL meter, and with exactly the same EQ settings, same cables, same sources. The PLX sounds better to me overall, but the GX3 seems to "rock a little bit harder" if you know what I mean. I've tried not to let the price difference sway my opinion.

The GX3 is not as quite as dynamic on swings from the lowest levels to the loudest peaks. It sounds a tad compressed compared to the 1104, but in doing so the GX3 seems subjectively slightly louder or more powerful at max level before clipping than the 1104 before clipping. It's not a huge difference, but I noticed it. The 1104 seems a bit more at ease, is more open and detailed pretty much across the spectrum, with more going on in the midrange/treble, where the GX3 sounds "darker" and more veiled, but a bit stronger in the bass range. You could describe it like switching between them sounded as if the EQ had been adjusted and a smidge of outboard compression/limiting had been used on the GX3.

I initially had thought the GX3's low end response and subjectively louder output was aided somewhat by having a built-in 20Hz HP filter as reported by Chris226, and thus some of the 1104's power was being wasted by not cutting off the band below 20Hz. But from another thread Thanh has said that both amps have only the built-in -3dB @ 6-8Hz subsonic filter to protect against 0Hz DC. So in that regard they're equal and thus cannot account for the differences I heard.

On the fan noise issue: when sitting behind my drum kit where the rack is at arm's reach or at lower output levels, I think the GX3's fan is more noticeable because of its higher pitch, where the 1104's fan has a lower pitch and not quite as loud overall. At some distance away or at higher levels you're not going to hear either fan. Also, maybe the GX3 fan spins at a higher RPM generally (?), and is mounted more towards the front of the case than the 1104's.

So, if you were to say one of these amps are "flat and neutral", then I would say the other one is not...since I heard noticeable differences between them due to the amps themselves and not room, equipment, or level change variables. Both amps sound good. For its intended purpose and price the GX3 is a bargain and to me sounds louder than 300 watts a side, while the 1104 seems generally more 'accurate'."

...


I'd add that the 1104 does not get the slam factor going on the 4725X's like the GX3 has. The 1104's 60-250Hz range is more subdued and needed some boost, while the range from around 2-8kHz needed taming. Even after changing EQ settings and at max output before clipping, the 1104 seemed a tad laid-back, smoother, more audiophile-ish, where the GX3 had more attack but was somewhat closed-in and less detailed compared to the 1104.

I found that both amps are a few dB less output than I'm going to need.

I'd guess that the "04" PLX's don't have the current that the "02" models have, or even as much as the GX series with similar WPC ratings. I'm still in the school that needs somewhat heavier iron (current) to produce very good bass slam and control, and even with all the high-tech switching power supplies that abound, 13-18 lb. amps don't seem to get you there. At the same time, I don't expect miracles from $300.-$500. amps.

I'm thinking trying about a Yamaha P series (P5000S or '7000). Anyone have experience with those? Or a RMX 2450 since I know they have some balls for the $$.

[scott fitlin]

Nice review! I, too, give QSC big thumbs up, A+++++!

I have a QSC Powerlight 6.0II, runs EIGHT JBL 2242H, 2 ohms per channel, up to 14 hours a day, 7 days a week, March thru October, NEVER QUITS, SOUNDS GREAT, and IT DON'T BREAK!

[LowPhreak]

Hey Scott - if I had the extra clams right now, I might go for a PL325 or 340, or E-V P series, or bigger '02 PLX, then shut the hell up and be happy.

I might get the 1804 and put up with less than stellar low end for the time being, then use it for the 4725X's as satellites where I think it would do a great job once I get a 4645C and another amp to drive that.

One good thing about buying a RMX or PLX right now is the rebate: http://www.qscaudio.com/rebate/rebate_10-2008.htm

But then there are the Yamaha's. I wish I knew how they sounded.

[Mike Caldwell]

As you noted that the amps were a few db short of what you needed. The cabinet you have are rated at 600 watts continuous so an amp in the 800 watt range would not be bad place to start. Be sure to watch clipping and have a high pass filter around 30hz in line at some point.

[LowPhreak]

Mike, I know the ratings of these and the whole thing about Continuous vs. Peak or Program, etc. I suppose ideally these would like 1000-1200w per side for good headroom, or the horns & woofer amped separately. Ultimately, that's what I hope to arrive at but it won't be soon.

The thing is, I'm trying to get half-decent sound & output for the time being for not a ton of cash, and I do realize there'll have to be some trade-offs in this price range. I'm going to be not more than about 16' from these cabs but I will run them at fairly high dB's at the listening position occasionally, and I like a strong bottom end if I can get it, but not at the expense of lousy mids/highs.

A lot of the stuff I listen to or practice on the drums has extended bass notes, not just peaky kick drum or bass guitar hits. When the 1104 is up on the "-10dB" light or just below clipping, I can hear it backing off in the low end on sustained notes. I really thought the 1104 or GX3 would be enough but I can see now they are not.

Right now I can get either a 1804 or 2450 for about the same price, and both have $100. MIR. I'm wondering which amp would be better for the 4725X's running full range for the time being. The way I see the pros & cons is:

~ RMX 2450-

1. Probably better current delivery on the low end, though a lower rated WPC. (?)

2. 30Hz HPF would help to not waste power, resulting in perhaps the same perceived loudness level as 600/wpc 1804. (?)...AND safety for the woofer.

3. Clip limiter can be turned off.

4. Use later for powering bridged mono sub.


~ PLX 1804-

1. Higher output than 2450 - about +3dB over the 1104, where the 2450's extra 100+ watts over the 1104 would perhaps not be noticeable.

2. Perhaps better sound overall than 2450, at least in the mids/highs. (?)

3. Use later for tops after I get a sub.


~ Yamaha P7000S -

1. Same price (but no MIR), higher WPC rating (700 @ 8/950 @ 4 ohms, etc.).

2. Sweepable HPF, bridgeable to 1900w/8 ohms for sub.

3. Can't find much opinion on comparisons to RMX & PLX amps re sound quality.



With the 1804's higher output, I'm worried that without a HPF it might cause excessive cone excursion below the low 30's. But if I use it just under clipping it might be OK. I don't know, but what's a clean 500-600w signal at sub-30Hz frequencies going to do to that 2226H?

I bought these cabs because they were virtually brand-new at dealer cost (or even below), and already knew I like their sound. Many here have a lot more experience with them, so I'm fishing for a few suggestions considering the current budget restrictions.

Any ideas, flames, criticisms, or comments are greatly appreciated!


EDIT: BTW, I've done a fair amount of searching/reading on QSC and ProSoundWeb forums, and I haven't found a good consensus yet for these cabs and these amps for my purposes. Most of those guys are using these for SR or live sound, DJ'ing, what have you, but that's different than my needs.

[Mike Caldwell]

At 30hz and below driven with 500 watts or so the 2226 will be working really hard and souning like it! Those cabinets are tuned to 35hz

[LowPhreak]

Well OK, what's a few Hertz amongst friends? Seriously though, I thought I read somewhere that Driverack specs the HPF for 4725X's (or was it SRX715's) as Butterworth -18dB @ 31.5 Hz? So a -12dB @ 35Hz or so would be in the ballpark for the 4725X.

[LowPhreak]

Well gents, for the money spent and after a couple weeks listening, I don't think I'd be entirely happy with the PLX's response in the long run. Not to disparage them - they're fine amps for various reasons and I have no prob recommending them, but they (1104 & 1804) don't seem to have quite the "drive" and bottom end I'm looking for.

I've been taking a look at EV's relatively new Q-series. There's an EV rep for the upstate NY region that is trying to get me a Q99 or Q1212 for a home demo, even though the pro audio shop I usually buy from isn't an EV dealer. This is great news, and above the call of duty for both the rep and the dealer (assuming the dealer goes along with it, and we think he may). I was very impressed with the rep's willingness to help on this.

Since the rep's experience is also from the "audiophile" end of things as mine is, as well as myself coming from a bit of live sound background being a drummer, we were discussing various power supply & amp circuit topologies and philosophies. From what I've gathered so far, I like what EV has been doing with the Q and the CP series.

Price-wise, a Q99 for example will cost more than a similar wattage 1804 and no rebates with the Q's, but it may run the 4725X's better for my purposes overall. We'll have to see about that!

Meanwhile, I'll continue to post my impressions, inane ramblings, and rants here, just in case anyone cares to read them.

[scott fitlin]

Unfortunately, while manufacturers offer some great bang for the buck, economical lines of amplification, I, too, find that although most of these lower price lines sound good, and do work, they usually do not have the highest level of performance. This is not say that they are bad, just that the more affordably priced lines don't have the nnnth degree of performance.

IMO, manufacturers premium lines cost more, but we get more. Amps that produce sub bass with BALLS, outstanding fidelity, motion control, and super long term reliability at very low impedances.

I, also, find premium equipment to be quite expensive, and say "OUCH" when I have to pay for it, but, when I hook it up, my ears go "YEAH BABY".

I hear you, prices are insane, but, OTOH, there does need to be a reason to pay the extra coin to own the top of the line items.

[LowPhreak]

Yes, seems that it's always been thus. You just can't escape very cheaply.

[allen mueller]

See if you can track down a pl325 to try. I have one and its a great amp. I've had rmx, plx, plx2 and now the pl325 and it is worth the price as you step up.


Allen