Members ToddAnisman Posted May 28, 2015 Members Share Posted May 28, 2015 We bought 3 QSC PLD 4.5's and two of them failed last week at the Lightning In a Bottle Festival. They failed at different times, seemingly on Startup. One I smelled the magic smoke come out of, it happened right after a power failure. We brought the system up and poof! Making me realize how fragile some of these modern amps are? unsure. I am taking them into QSC tomorrow, and will hopefully get the reason for the failure then. I do think that QSC has made at least one error on these... - I'm pretty sure that they can pull way more than 20a when in 4 channel mode. I def saw the log spike a few times. We had constant power issues early on before the failures, but once i made the power people switch the gennie & distro out, it got much more stable. Both Failures occured after that point. Here's a link to the mayhem... System sounded AMAZING before that. 4 Danley SH46's/ 6 Danley TH118's. each running of its own channel of a QSC PLD 4.5 sound was amazing. Link to comment Share on other sites More sharing options...
Members dboomer Posted May 28, 2015 Members Share Posted May 28, 2015 Were these brand new amps? Infant Mortality Syndrome ? I didn't see a spec for power consumption ... but if this amp can actually put out 5000W it will certainly take more than 20A @120V to do it. But I don't expect you'll ever actually come close for more than milliseconds running music through it. It was very nice to see this in their OM. 1/8 Power Thermal loss at 1/8 of full power is measured with pink noise. It approximates operating with music or voice with light clipping and represents the amplifier's typical "clean" maximum level, without audible clipping. Use these figures for typical maximum level operation. 1/3 Power Thermal loss at 1/3 of full power is measured with pink noise. It approximates operating with music or voice with very heavy clipping and a very compressed dynamic range. Full Power Thermal loss at full power is measured with a 1 kHz sine wave. However, it does not represent any real-world operating condition. Link to comment Share on other sites More sharing options...
Members ToddAnisman Posted May 28, 2015 Author Members Share Posted May 28, 2015 I suppose tit could have been IMS.. hehe but not their first use. we used them in Mexico, and at another festival, all on gennie power and they performed flawlessly. I was confidant in them to take the to such a high profile event. I was very skeptical as well on the power consumption - enough so that I sent my assistant to the QSC booth at NAMM to ask that very question - and they said "Yes" and they put an Edison Nema 15 plug on the amp. so that indicates that its good to go at that power level. But if its not - thats fine. and FWIW - these were L21-30 distro's that were 30a. Yes to edison. Janky? perhaps but common at festivals. SO the circuits were ostensibly 30a (10/5 run out of the distro box, which was 6/5, 50'). One amp per leg. I shouldn't have popped them. but yet we did. and the suck thing about that type of distro is that the whole leg goes down, not just the individual circuit.... Link to comment Share on other sites More sharing options...
Members Pro Sound Guy Posted May 28, 2015 Members Share Posted May 28, 2015 A few things to look at.The amps have been working fine up until a show where you have indicated AC issues.Amp fuses? Internal?For two amps to fail at the same time because of the amps themselves is probably almost nil. Link to comment Share on other sites More sharing options...
Members Audiopyle Sound Posted May 29, 2015 Members Share Posted May 29, 2015 ...and FWIW - these were L21-30 distro's that were 30a. Yes to edison. Janky? perhaps but common at festivals. SO the circuits were ostensibly 30a (10/5 run out of the distro box, which was 6/5, 50'). One amp per leg. I shouldn't have popped them. but yet we did. and the suck thing about that type of distro is that the whole leg goes down, not just the individual circuit.... If you were running 30a feeder straight to edisons without smaller breakers as you seem to imply here I'm surprised it didn't catch fire. Link to comment Share on other sites More sharing options...
Members agedhorse Posted May 30, 2015 Members Share Posted May 30, 2015 Regarding the L21-30 distro (I had a lot of this stuff), it's unlikely that the amp would catch fire because the amp itself has it's own overcurrent protection. The 3 pole distro breaker just protects the branch circuit runs. You should not have opened the 30 amp breakers, the amp's inrush current limiting should prevent this BUT if the inrush current limiting circuit (there are several ways to do this) failed, this could certainly be the result. Link to comment Share on other sites More sharing options...
Members ToddAnisman Posted May 30, 2015 Author Members Share Posted May 30, 2015 The amps logs will tell the tale once QSC analyzes them. I am def curious. the damn breaker went waaaaay too many times. It was much better after I made the festival switch out the distro, but thats also when the failures occurred. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted May 30, 2015 CMS Author Share Posted May 30, 2015 Incidentally, I did a review of this amp last year, and it took months to do so. The first two amps QSC sent failed on startup..."boot failure error" was the display message. The 1st unit was preproduction and I'm pretty sure I wasn't the first user, the second was production and was fresh from the box sent to me (which doesn't necessarily mean it was brand new). After months of waiting after that, I received another production unit that performed flawlessly, and which I thrashed and racked up hundreds of hours without a hiccup. I didn't get any answers as to the prior unit failures, but being a new model and pretty sophisticated, it wasn't too important to me at the time...stuff happens in product development. I too would be more suspicious of the power distro issues you experienced. That many failures of units that were working previously is far too coincidental. Link to comment Share on other sites More sharing options...
Members ToddAnisman Posted June 1, 2015 Author Members Share Posted June 1, 2015 I agree. Tuesday will be interesting! (I get them back then). Craig I read your reviews before i bought them amps, and i felt it was so out of character for QSC i didnt give the failure much weight - but QSC is Turning them around quick, so i cant reallycomplain at all. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted June 1, 2015 CMS Author Share Posted June 1, 2015 I agree. Tuesday will be interesting! (I get them back then). Craig I read your reviews before i bought them amps' date=' and i felt it was so out of character for QSC i didnt give the failure much weight - but QSC is Turning them around quick, so i cant reallycomplain at all.[/quote'] It was a difficult issue for me. I agree; QSC has an outstanding reputation for solid products and outstanding support. However I wasn't favorably impressed with the fact that I got zero feedback from them regarding not one but two consecutive and identical failures of a flagship-level new product. I thought, "what would I be writing if it was any other manufacturer...perhaps one like Behringer?" I could have ignored this issue in my review, I could have lambasted them for the lack of feedback, or I could simply mention what happened and let the reader decide where this issue falls. I chose the latter, and hope it was the right choice. Link to comment Share on other sites More sharing options...
Members Unalaska Posted June 1, 2015 Members Share Posted June 1, 2015 I think this is treading into needlessly complicated stuff for end users. The price point is right: one 4ch amp = 2x plx 2 channel amps. The DSP and routing are free. But the DSP for the average non studied user is confusing. Installation, yeah, controlled environment yeah. I personally wouldn't want someone changing a parameter and something fatal happens downstream. Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 2, 2015 Members Share Posted June 2, 2015 I agree, I was going through my system DSP's and found that one eq module in one unit had gotten changed. Minor difference but it shouldn't have happened. AND, I don't know how it could have happened either. Mistakes do happen, and really serious (read as costly) ones too. Link to comment Share on other sites More sharing options...
Members ToddAnisman Posted June 2, 2015 Author Members Share Posted June 2, 2015 What exactly is needlessly complicated? It either a separate dsp or in the amp, what does it matter? Im not sure what the "needless" part is - isnt all of it required? Edit: I should add aside from the normal reliablity argument etc... Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted June 2, 2015 CMS Author Share Posted June 2, 2015 In the context of the PLD 4.5, I have to agree with Todd. The DSP is no more dangerous in the PLD than any separate driverack. But you have the option of enabling a password-protected lockout. Once you've got your setting, lock out the menus, and the only controls that work are the power buttons and mute. Given that the DSP is built in, that's about as much protection as you can ask for. Link to comment Share on other sites More sharing options...
Members Pro Sound Guy Posted June 2, 2015 Members Share Posted June 2, 2015 Save your settings in the unit and reflash the file settings you want to use evertime you turn it on.I make it a habit to go through all the pages throughout the processor before use and make sure every T is crossed and every I dotted.Something easy to miss can make a difference like a simple setting for a delay between two drivers or boxes.Craig is right about locking it via password if there is more then one set of hands that can get on your processing settings Patiently waiting for just what happened with the QSC amps....tap tap tap Link to comment Share on other sites More sharing options...
Members Unalaska Posted June 4, 2015 Members Share Posted June 4, 2015 Remember these amps can combine out power into a single channel digitally. That's something you want to know before powering up a new system. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted June 6, 2015 CMS Author Share Posted June 6, 2015 Remember these amps can combine out power into a single channel digitally. That's something you want to know before powering up a new system. Yes, it helps to know that the power button is also the global mute....push it once momentarily. Link to comment Share on other sites More sharing options...
Members ToddAnisman Posted July 1, 2015 Author Members Share Posted July 1, 2015 Following back up on this... Had another issue out int he field recently.. again on generator power. One unit would not go into its boot cycle on the last night of a 3 day event... it simply would not boot, gave a message that it could not load operating system... with a computer i was able to hook it up via usb, and the amp was reporting low Voltage - 87volts... which was weird. i grabbed our backups and kept going, but once I got it home I blew it out, and now its fine. this is odd. Bottom line these amps are not on the QSC PLX level of reliability.... which is a real bummer. I Will likely swap them out for PL380's.. which is i guess what i should have done from the start. Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 1, 2015 Members Share Posted July 1, 2015 I've been using PLX's for years, have a large number of them, and have had only one problem out of a couple dozen amps in 10 years. Link to comment Share on other sites More sharing options...
Members ToddAnisman Posted July 1, 2015 Author Members Share Posted July 1, 2015 I've been using PLX's for years' date=' have a large number of them, and have had only one problem out of a couple dozen amps in 10 years. [/quote'] Yep I have 5 3402's and one 3002, and have not had a failure and some amps have 7 years of intense Burning Man-Esque work on them. these new PLD's however are either stupid Touchy or prone to failure. Im am not confidant in them. ahh well. The only other QSC amp i've had fail on recently was a PL 1.8 after getting nailed with a floating neutral power issue. I should point out that the failures have occurred on them Sub Amps, not the top amps, (which have a lighter duty).. so I wonder if that is the issue. I run the amps in AB - CD mode (two sections parralleled, for an output of 2250w/4Ohm, them limited to 1750w) current gets up there, around 18a in spikes. Gennie was a Honda EU6500i, which was also running the Top Amp (also a QSC PLD4.5). I will say that voltages were a touch high - 128v off the gennie. that is HIGH, but not all that uncommon... and the power supply on the PLD is universal 100-240v. SO im a touch baffled. i have sent an email to QSC to ask them if they have any insight. Todd A. Link to comment Share on other sites More sharing options...
Members Tomm Williams Posted July 1, 2015 Members Share Posted July 1, 2015 I've been using PLX's for years' date=' have a large number of them, and have had only one problem out of a couple dozen amps in 10 years. [/quote'] Didn't we have pretty much this same conversation today ? Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 1, 2015 Members Share Posted July 1, 2015 Didn't we have pretty much this same conversation today ? Yup, sometimes lower tech inspires greater confidence. Money alone can't buy confidence, but good (appropriate) choices can. Link to comment Share on other sites More sharing options...
Members Two of Seven Posted July 1, 2015 Members Share Posted July 1, 2015 I agree, I was going through my system DSP's and found that one eq module in one unit had gotten changed. Minor difference but it shouldn't have happened. AND, I don't know how it could have happened either. Mistakes do happen, and really serious (read as costly) ones too. I had a DSP setting change mysteriously once too. Behringer DCX 2496. One show my subs were just a bit “off ” sounding. Chalked it up to the room or my ears. Back at home dug into it and believe it or not – a phase adjustment setting on one sub channel was apparently active, but a value did not show on the display. As soon as I was in edit mode for phase the unit “clicked “ back into correct phase and the subs returned to normal. I could recreate the sound by putting one sub some fraction, something like 45*IIRC, out of phase. And this was a preset that had no phase adjustments incorporated in it. Link to comment Share on other sites More sharing options...
Members ToddAnisman Posted July 1, 2015 Author Members Share Posted July 1, 2015 That's behringer for ya Andy/Tomm - Yep. thats that case here. I made a decision that im kinda regretting; I feel i should have gone with the PL380, old fashioned dsp and figured out all the limiting math and all that jazz... I def got caught by the ideal of easy reconfiguration, Built in DSP, and all that. The question is what to do now. Todd A. Link to comment Share on other sites More sharing options...
Members Tomm Williams Posted July 1, 2015 Members Share Posted July 1, 2015 That's behringer for ya Andy/Tomm - Yep. thats that case here. I made a decision that im kinda regretting; I feel i should have gone with the PL380, old fashioned dsp and figured out all the limiting math and all that jazz... I def got caught by the ideal of easy reconfiguration, Built in DSP, and all that. The question is what to do now. Todd A. Feel your pain Todd, with Andy's help I just finished switching completely over to PLX amps. I had a good number of a certain brand of amp that failed me repeatedly under the oddest of circumstances. I refrain from naming them as they were stellar in their willingness to repair no-questions-asked. However that impeccable service isn't much comfort when you have an amp go down AGAIN in the middle of an event. Cannot do business like that. Some folks might take issue with me not wanting to name names so just let me say................buy PLX and the rest is irrelevant. Link to comment Share on other sites More sharing options...
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