New Power Amplifiers??

Re: New Power Amplifiers??

Vinny D'Agostino said:
I don't like the idea of one amplifier, if it goes down at a show I have no options. Using two amps at least gives me a chance to limp thru the night should one go down.
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Keep your PLX or something, and leave it in the truck. The newer Itechs and Macrotech i amps have taken care of most of the bad reliability issues the old Itechs had, leaving them about the same chance of failing as anything else in your signal chain. The QSC PL3 series is rock solid from what I have heard, also. Do you carry backup mixers, crossovers or DSPs, speakers, etc?
 
Re: New Power Amplifiers??

Tim McCulloch said:
Yes, if that's all you need done... and with the 5Ki, you have input compression, output limiting (both peak voltage and RMS power), load monitoring, input/output level monitoring and fault reporting, all that can be done via System Architect.

http://www.crownaudio.com/pdf/amps/140579.pdf will begin your fun, the software-adjustable stuff begins on page 22.
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The RMS and Peak voltage limiters are great and come in handy. I just got a pair of new EV QRX 212/75's. I don't have an amp for them yet so I hooked them up to my sub amp, a Crown MA12Ki. I set the RMS/Peak parameters temporarily to match my QRX's, along with using a PC running the System Architect software to monitor the amps input/output and limit levels. This lessened the fear of blowing them up.
 
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Re: New Power Amplifiers??

Tim McCulloch said:
Hi Vinnie-

As much as I like new amps, I think what you need is a RAMP. The fold-up ''accessibility'' ramps are cool and will support 400#.
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I think Vinny has already solved his amp issue, but I thought I'd add to the conversation that I picked up a Harbor Freight folding ramp for $129 on Monday while I was down in the states and I'm very pleased.

http://www.harborfreight.com/1200-lb-capacity-convertible-aluminum-loading-ramp-94057.html

It's says rated for 1200 lbs (evenly distributed) but I pushed up a 400 lbs case plus me (225) and it was about as springy as I would care for. That said, it will be more than adequate for all my needs and the design worked very well for my trailer without a ramp. If I was there again I would probably buy a second one for the times when more than one obstacle is encountered on load in.

I'm also going to look for a 10' ramp to facilitate trailer to dock loading, but Quebec just changed our heavy vehicle rules to be a but friendlier on the small side, so I may end up with a box truck anyways...
 

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Re: New Power Amplifiers??

Jeffrey Knorr said:
AC watts != Audio watts

We've run a pair of QSC PL380's at 2-3 Ohms/channel along with everything else before off of one 20A circuit. Would I recommend this all the time? No, but it can work and work well in a combat audio situation.

Jeff
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AC watts will always be higher than the actual watts that are delivered to your speaker. The rest of the watts are lost as heat from the amp. With your 2 amps on one circuit, there is no way you can deliver the rated power of the amps for any duration without blowing a breaker. Remember that the clip light will start to flicker at 1/8 power. The pl380 is rated at 8000 watts, loaded to the hilt. That means when the clip light starts to flicker, its giving you 1000 watts at the peaks. Music being dynamic means the average wattage will be much less than that.

How dynamic depends on the type of music. Play some heavily compressed club music and you will be making a trip to the breaker panel real soon. For a live band where you never see the clip light, you will probably be just fine.
 
Re: New Power Amplifiers??

Brian jojade said:
Remember that the clip light will start to flicker at 1/8 power. The pl380 is rated at 8000 watts, loaded to the hilt. That means when the clip light starts to flicker, its giving you 1000 watts at the peaks. Music being dynamic means the average wattage will be much less than that.
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Wouldn't it be giving "8000 watts" peak, but maybe 1,000 watts of actual heating (RMS) power? I don't know how the clip light knows anything about the crest factor of the signal...
 
Re: New Power Amplifiers??

Bennett Prescott said:
Wouldn't it be giving "8000 watts" peak, but maybe 1,000 watts of actual heating (RMS) power? I don't know how the clip light knows anything about the crest factor of the signal...
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yup.. I was wondering about that too... Clip lights by definition should be indicating "clipping", not 9 dB or whatever nominal amount below clipping. I have make "peak" or "OL" (overload) LEDs in consoles indicate before clipping and I am suspicious of some amp designers, indicating clip, a little after clip for the extra perceived power output.

I still think power amps need peak "and" average metering, but nowadays we're lucky to get any meters at all... :-(

JR
 
Re: New Power Amplifiers??

John Roberts said:
yup.. I was wondering about that too... Clip lights by definition should be indicating "clipping", not 9 dB or whatever nominal amount below clipping. I have make "peak" or "OL" (overload) LEDs in consoles indicate before clipping and I am suspicious of some amp designers, indicating clip, a little after clip for the extra perceived power output.

I still think power amps need peak "and" average metering, but nowadays we're lucky to get any meters at all... :-(

JR
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Not to sound like the Crown fanboy, but the Itechs and Macrotech i series have both peak and average limiting. It's quite interesting to see, at a show, that while the kick is approaching clip on the sub amp, the average is at -20dB from clip. Shows how useful the added peak power could be.
 
Re: New Power Amplifiers??

Silas Pradetto said:
Not to sound like the Crown fanboy, but the Itechs and Macrotech i series have both peak and average limiting. It's quite interesting to see, at a show, that while the kick is approaching clip on the sub amp, the average is at -20dB from clip. Shows how useful the added peak power could be.
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You do sound like a crown fanboy. Any system processor with metering after the crossover would give you that information. Silas, if you have THAT much disparity between your subs and tops, it sounds to me that you can't blame an amp for not producing enough output. The system is just improperly deployed or you've severly underestimated the efficiency/output of your subs.
 
Re: New Power Amplifiers??

Silas Pradetto said:
Not to sound like the Crown fanboy, but the Itechs and Macrotech i series have both peak and average limiting. It's quite interesting to see, at a show, that while the kick is approaching clip on the sub amp, the average is at -20dB from clip. Shows how useful the added peak power could be.
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That is logical... I recall seeing one older QSC amp with rear panel dip switches that supported peak and ave limiting. I'm not sure many customers embrace the concept or would know how to set it.

I built average limiting into a fixed install amp, where the 150W standard amp was too much power for some installations, so they could just turn down the speaker melting power, this was about $0.50 parts added to the existing DDT clip limiter.

I still think Peak/Ave metering might remove some of the confusion, if people believe they have clip LEDs lighting up prematurely. Or perhaps they just need a vocabulary refresh, about what clipping is.

JR
 
Re: New Power Amplifiers??

Marlow Wilson said:
I think Vinny has already solved his amp issue, but I thought I'd add to the conversation that I picked up a Harbor Freight folding ramp for $129 on Monday while I was down in the states and I'm very pleased.

http://www.harborfreight.com/1200-lb-capacity-convertible-aluminum-loading-ramp-94057.html

It's says rated for 1200 lbs (evenly distributed) but I pushed up a 400 lbs case plus me (225) and it was about as springy as I would care for. That said, it will be more than adequate for all my needs and the design worked very well for my trailer without a ramp. If I was there again I would probably buy a second one for the times when more than one obstacle is encountered on load in.

I'm also going to look for a 10' ramp to facilitate trailer to dock loading, but Quebec just changed our heavy vehicle rules to be a but friendlier on the small side, so I may end up with a box truck anyways...
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Marlow, I haven't tried that model but I have their steel ones, which are not springy at all, whether using them to load a 300 lb. generator, a 400 lb. woodchipper, or a 650 lb. yard tractor. Might be a little heavier than the aluminum set, but not unreasonably so.
 
Re: New Power Amplifiers??

Mike Butler (media) said:
Marlow, I haven't tried that model but I have their steel ones, which are not springy at all, whether using them to load a 300 lb. generator, a 400 lb. woodchipper, or a 650 lb. yard tractor. Might be a little heavier than the aluminum set, but not unreasonably so.
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None of the steel ones I saw were smooth enough for loading things with smaller wheels. I should also add that I pulled this out of the box in a snowy parking lot and lost one of the three nuts, so the first use just had two of three of the bolts and the two there were only finger tight, but they don't really do much anyways. I was loading a huge case with two 60" plasma screens and a bunch of hardware and had to lift one end as I was standing right in the middle of the ramp, so a LOT of weight was concentrated and I was moving it somewhat clumsily. The real point I was trying to make is this isn't a real ramp like you'd find on a box truck despite a having a similar weight rating, but for loungers it's more than adequate.
 
Re: New Power Amplifiers??

Vinny D'Agostino said:
For the amps I am looking for they need to be in the area of 1500w @ 4ohms per channel (a little more would not be a bad thing)
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I'm a bit late to this thread - but I'd have considered bridged IPR1600's. You'd need 3 (or 4?) of them but at < 7lbs each and a shallow depth you can still get 3 into a Gator GR-6S case and carry two of them racks at a time, one in each hand :D .

BTW I put an IPR3000 into a 2U SKB shallow rack (shallower than the Gator) and it just fit with a 1/4" to spare - about right to power my two 4 ohm Rog designed folded horns and I can lift it with one finger :D . I too would have rather gone with a single IPR4500 to run both subs and tops in mono but who knows when they will ever come out?
 
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Re: New Power Amplifiers??

Ron Kimball said:
That'll do it! What do you carry as backup? I try to have a spare 2450 on hand but dunno how I'd backup a 8000 that is driving you entire FOH :shock: .
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I'm pretty sure it's on his subs only, so he still has plenty of amps when you factor in monitors. In the unlikely event of failure I'm sure most of us could limp along with everything else he's got there amp wise.
 
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