Members sbrett Posted December 4, 2012 Members Share Posted December 4, 2012 Originally Posted by Gypsy Kiss Originally Posted by Mutha Goose Earlier you stated that the amps should not run hotter when running idle. So we corrected that mis-statement... to that you reply with a different argument about a different point. Are you trying to learn more or argue? Always trying to learn more... So when do you reach the point of "too hot" for a digital amp? or even , "wow, that's getting pretty hot" maybe we should allow a little headroom?? ... Why did JBL design an amp that runs so hot you can fry an egg on the back???...My point is why would you want to run any amp that hot? even if the numbers say it works, show me another digital active speaker that runs that hot??? Just trying to get my head around the logic behind the design. Something tells me they don't all run 'that hot'. Ours have never gotten as hot as what some of you have experienced. Not sure what that means. Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 5, 2012 Members Share Posted December 5, 2012 Originally Posted by sbrett Something tells me they don't all run 'that hot'. Ours have never gotten as hot as what some of you have experienced. Not sure what that means. Really?, I would be relieved if this were indeed the case? maybe mine are defective??, should I return them for another pair?. But my JBL rep says the amps will run at 60 Degrees +, which to JBL is considered normal operating temps? to me that's really hot????? Link to comment Share on other sites More sharing options...
Members 9-Pin-Phoenix Posted December 5, 2012 Members Share Posted December 5, 2012 Originally Posted by Gypsy Kiss Really?, I would be relieved if this were indeed the case? maybe mine are defective??, should I return them for another pair?. But my JBL rep says the amps will run at 60 Degrees +, which to JBL is considered normal operating temps? to me that's really hot????? But based on what I understand from this thread, JBL's operating temps are what is important, not what you consider hot. In fact, you may be operating your speakers outside of optimal range by bringing the temperature down. Link to comment Share on other sites More sharing options...
Members Mutha Goose Posted December 5, 2012 Members Share Posted December 5, 2012 It is not unreasonable that a "1500 Watt" amp can run 60 Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 5, 2012 Members Share Posted December 5, 2012 Originally Posted by 9-Pin-Phoenix But based on what I understand from this thread, JBL's operating temps are what is important, not what you consider hot. In fact, you may be operating your speakers outside of optimal range by bringing the temperature down. Can you or somebody actually confirm this please? That running fans on the 635's is detrimental to the optimum performance of the cab??.. Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 5, 2012 Members Share Posted December 5, 2012 Originally Posted by Mutha Goose It is not unreasonable that a "1500 Watt" amp can run 60 Link to comment Share on other sites More sharing options...
Members agedhorse Posted December 5, 2012 Members Share Posted December 5, 2012 60 degrees c is not an issue and is right in the middle of the operating temp range for modern mosfets. That's hot to the touch but not hot for a MOSFET. Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 5, 2012 Members Share Posted December 5, 2012 Originally Posted by agedhorse 60 degrees c is not an issue and is right in the middle of the operating temp range for modern mosfets. That's hot to the touch but not hot for a MOSFET. OK, but will running fans on the back be harming the performance or damaging the box??. And how come my EV's don't run half that hot??. Link to comment Share on other sites More sharing options...
Members agedhorse Posted December 5, 2012 Members Share Posted December 5, 2012 Originally Posted by Gypsy Kiss OK, but will running fans on the back be harming the performance or damaging the box??. I don't know, it's not one of my products and I haven't done this kind of testing on it. Testing for things like this are costly and time consuming, but essential if you want to understand the parameters of the design. I'm positive that JBL has done extensive testing on their products and I do on mine and I'm sure Goose does on his. Originally Posted by Gypsy Kiss And how come my EV's don't run half that hot??. Because they are not the same amplifier design. You also do not know the temperature of each of the individual internal components, some of which may be running much hotter. Link to comment Share on other sites More sharing options...
Members dboomer Posted December 5, 2012 Members Share Posted December 5, 2012 Can you or somebody actually confirm this please? That running fans on the 635's is detrimental to the optimum performance of the cab??.. Highly doubtful using common fans that it would cause any issues. I'm assuming that you are only cooling with these fans and not stirring up turbulence to the acoustic output. Why run the amp on "the high side"??..would it not be more logical to run it on the "low side" It's a non-issue. Thishis design takes that into consideration. Other designs are different. You are assigning value to one design over the other which may or may not have anything to do with the primary job of the amplifier. Their decision is probably made on a cost/benefit basis and there is probably no benefit for the cost. Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 5, 2012 Members Share Posted December 5, 2012 OK, Thanks for all the input Aged and DB and everyone else who chimed in . I think I might just take the cabs to my local Tech ( who is a authorized JBL repairer) and discuss this further with him. I really love the sound/weight/look of these cabs so I'm very willing to keep them, just want to nail this heat thing... Link to comment Share on other sites More sharing options...
Members Hegmatronicon Posted December 6, 2012 Members Share Posted December 6, 2012 Wow dude. Either you are REALLY not understanding what's being said, or you are being deliberately dense. To sum up - there is no issue. YOU are the issue. Or rather - you have an issue with how something runs, when it's running 100% correctly. May i suggest you take your car to the mechanic and see what he can do about all the heat in the exhaust system? That's far too hot to touch. Must be a problem. Link to comment Share on other sites More sharing options...
Members Mutha Goose Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by Gypsy Kiss And how come my EV's don't run half that hot?? Originally Posted by Gypsy Kiss ... I really love the sound/weight/look of these cabs... Heatsinks add weight. Link to comment Share on other sites More sharing options...
Members Mutha Goose Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by agedhorse ... I'm positive that JBL has done extensive testing on their products and I do on mine and I'm sure Goose does on his... ...and then some! Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by Hegmatronicon Wow dude.Either you are REALLY not understanding what's being said, or you are being deliberately dense.To sum up - there is no issue. YOU are the issue. Or rather - you have an issue with how something runs, when it's running 100% correctly.May i suggest you take your car to the mechanic and see what he can do about all the heat in the exhaust system? That's far too hot to touch. Must be a problem. Geeze, thanks for clearing that up, and it ain't just me, do some research and you will find there are a lot of other PRX users out there that have the same concerns of the excessive heat these things produce and while obviously we all can't be amazingly tech brilliant such as yourself , I certainly haven't lowered myself to calling people "dense" (not yet anyhow..lol) . Lots of reported thermo issues and while I will agree with what Aged has stated and others, that some of these problems have stemmed from improper use (ie : driving the crap out of them) I'm sure in amongst all the thermo reports there are quite a few guys/gals that do know what they are doing, and after using these 635's for the last month I can fully understand why there are concerns out there....THEY GET HOT....DAMN HOT!!! and while I understand that they have been designed to run that way it still worry's me . Heat kills, may not be today or next week/month but eventually it kills....Even your exhaust... Link to comment Share on other sites More sharing options...
Members Hegmatronicon Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by Gypsy Kiss Geeze, thanks for clearing that up, and it ain't just me, do some research and you will find there are a lot of other PRX users out there that have the same concerns of the excessive heat these things produce and while obviously we all can't be amazingly tech brilliant such as yourself , I certainly haven't lowered myself to calling people "dense" (not yet anyhow..lol) . Lots of reported thermo issues and while I will agree with what Aged has stated and others, that some of these problems have stemmed from improper use (ie : driving the crap out of them) I'm sure in amongst all the thermo reports there are quite a few guys/gals that do know what they are doing, and after using these 635's for the last month I can fully understand why there are concerns out there....THEY GET HOT....DAMN HOT!!! and while I understand that they have been designed to run that way it still worry's me . Heat kills, may not be today or next week/month but eventually it kills....Even your exhaust... They are designed to run that way - but you are worried.Yeah ok.Go see your tech then. Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by Hegmatronicon They are designed to run that way - but you are worried.Yeah ok.Go see your tech then. Thanks for your blessing.. I'm worried cause of the reported shutdowns ( sometimes at idle) due to excessive heat and if there weren't then I would not be worried.....Hope that didn't sound to dense for ya.. Link to comment Share on other sites More sharing options...
Members sibyrnes Posted December 6, 2012 Members Share Posted December 6, 2012 I wish there was some real, accurate info about failure rates. All we have is anecdotal evidence. Heck, mine have been running hot for two years without trouble. I trust the engineers at JBL - so far! Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by sibyrnes I wish there was some real, accurate info about failure rates. All we have is anecdotal evidence. Heck, mine have been running hot for two years without trouble. I trust the engineers at JBL - so far! That"s a good sign I guess . I did receive an email from a PA guy who I know to be very up to speed with techie stuff sort of guy and he has had the JBL PRX stuff shutdown on him mid gig due to the cabs overheating (he did not mention what model) but he did say he was surprised at how hot the amps did run,and like Aged and Goose, had total faith in the team at JBL/Crown . I'm sure there are heaps of PRX users such as yourself who have had zero probs with them but when this problem keeps popping up it has to make you wonder??..Well I worry... Anyways the fans I run on the back keep things nice and luke warm and that makes me feel much better, but I still want to take them to my Tech who I know very well and I think will give me a totally unbiased opinion on what he thinks...We shall see.... Link to comment Share on other sites More sharing options...
Members Mutha Goose Posted December 6, 2012 Members Share Posted December 6, 2012 Gypsy: Please understand, I am not saying there is or isn't a problem with the PRX635. I don't have enough data to make that determination. You had a lot of "why" questions about the thermal design mixed with some (understandably) wrong impressions, so that is all I was clarifying. Design is a great art of compromise. I can easily envision the conversations between the design team that wants to reduce temperature a little, and the marketing group that wants to hit a specific weight and cost target while maintaining visual continuity across the product line. Personally, I own PRX612s and 618XLFs and have since they came out (I was an early adopter). I am also friendly with other providers in my area with various PRX boxes. I have been hearing stories about how "hot the PRX's run" for almost as long. But from my perspective, I do not agree with that. I know what kinds of temperature rises to expect, and I haven't felt anything that concerns me (and I have run many outdoor shows in the sun as well).As to failure rates and thermal-shut-downs: Again, I have not experienced this myself, nor has anyone I personally know. However, my girlfriend's sister is friends with someone who's hairdresser's boyfriend read on the internet that someone he heard of knew someone that had experienced this problem so it must be a pervasive issue requiring a recall and immediate corrective action! (JK) In the consumer product industry, delivered quality averages can be pretty high (>5% failure out of the box or higher depending...). I have no idea where the PRX line, or more specifically the 635, run. But let's just say for conversation that these are performing wonderfully at 0.5%, with a target audience being DJ's (who tend to be very active online). If JBL sold only 10,000 boxes, there would be 50 people screaming online about what a piece of {censored} this box is. Put 100,000 in the field and you now have 500 people screaming in unison. That can be pretty loud. But does it mean there is a real problem?... only if you're one of those 500. It doesn't make it any less an issue for those 500, but that is what it is. But now to reduce that number, cost has to go way up. So now, you increase the weight and the price on 100% of the product to see a delivered quality reduction to 0.4%. Was it worth it? OK, so let's provide even more margin and reduce the incident rate to 0.3%, but now the cost to gain an additional 0.1% cost 10X what the first 0.1% reduction cost... now, is that worth it? Where's the line? That is up to JBL to decide. But I can tell you this; wherever it is, there will be someone on the wrong side of that line screaming about what a piece of {censored} that box is! Link to comment Share on other sites More sharing options...
Members lonotes Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by Mutha Goose However, my girlfriend's sister is friends with someone who's hairdresser's boyfriend read on the internet that someone he heard of knew someone that had experienced this problem... Were they discussing this last night at Baskin-Robbins? I hear it's serious. Link to comment Share on other sites More sharing options...
Members agedhorse Posted December 6, 2012 Members Share Posted December 6, 2012 This is IMO, a pretty accurate description of how the electronics world works. Originally Posted by Mutha Goose Gypsy: Please understand, I am not saying there is or isn't a problem with the PRX635. I don't have enough data to make that determination. You had a lot of "why" questions about the thermal design mixed with some (understandably) wrong impressions, so that is all I was clarifying. Design is a great art of compromise. I can easily envision the conversations between the design team that wants to reduce temperature a little, and the marketing group that wants to hit a specific weight and cost target while maintaining visual continuity across the product line. Personally, I own PRX612s and 618XLFs and have since they came out (I was an early adopter). I am also friendly with other providers in my area with various PRX boxes. I have been hearing stories about how "hot the PRX's run" for almost as long. But from my perspective, I do not agree with that. I know what kinds of temperature rises to expect, and I haven't felt anything that concerns me (and I have run many outdoor shows in the sun as well).As to failure rates and thermal-shut-downs: Again, I have not experienced this myself, nor has anyone I personally know. However, my girlfriend's sister is friends with someone who's hairdresser's boyfriend read on the internet that someone he heard of knew someone that had experienced this problem so it must be a pervasive issue requiring a recall and immediate corrective action! (JK) In the consumer product industry, delivered quality averages can be pretty high (>5% failure out of the box or higher depending...). I have no idea where the PRX line, or more specifically the 635, run. But let's just say for conversation that these are performing wonderfully at 0.5%, with a target audience being DJ's (who tend to be very active online). If JBL sold only 10,000 boxes, there would be 50 people screaming online about what a piece of {censored} this box is. Put 100,000 in the field and you now have 500 people screaming in unison. That can be pretty loud. But does it mean there is a real problem?... only if you're one of those 500. It doesn't make it any less an issue for those 500, but that is what it is. But now to reduce that number, cost has to go way up. So now, you increase the weight and the price on 100% of the product to see a delivered quality reduction to 0.4%. Was it worth it? OK, so let's provide even more margin and reduce the incident rate to 0.3%, but now the cost to gain an additional 0.1% cost 10X what the first 0.1% reduction cost... now, is that worth it? Where's the line? That is up to JBL to decide. But I can tell you this; wherever it is, there will be someone on the wrong side of that line screaming about what a piece of {censored} that box is! Link to comment Share on other sites More sharing options...
Members abzurd Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by agedhorse This is IMO, a pretty accurate description of how the electronics world works. Yep. Great post Mr. Goose. Link to comment Share on other sites More sharing options...
Members Gypsy Kiss Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by Mutha Goose Gypsy: Please understand, I am not saying there is or isn't a problem with the PRX635. I don't have enough data to make that determination. You had a lot of "why" questions about the thermal design mixed with some (understandably) wrong impressions, so that is all I was clarifying. Design is a great art of compromise. I can easily envision the conversations between the design team that wants to reduce temperature a little, and the marketing group that wants to hit a specific weight and cost target while maintaining visual continuity across the product line. Personally, I own PRX612s and 618XLFs and have since they came out (I was an early adopter). I am also friendly with other providers in my area with various PRX boxes. I have been hearing stories about how "hot the PRX's run" for almost as long. But from my perspective, I do not agree with that. I know what kinds of temperature rises to expect, and I haven't felt anything that concerns me (and I have run many outdoor shows in the sun as well).As to failure rates and thermal-shut-downs: Again, I have not experienced this myself, nor has anyone I personally know. However, my girlfriend's sister is friends with someone who's hairdresser's boyfriend read on the internet that someone he heard of knew someone that had experienced this problem so it must be a pervasive issue requiring a recall and immediate corrective action! (JK) In the consumer product industry, delivered quality averages can be pretty high (>5% failure out of the box or higher depending...). I have no idea where the PRX line, or more specifically the 635, run. But let's just say for conversation that these are performing wonderfully at 0.5%, with a target audience being DJ's (who tend to be very active online). If JBL sold only 10,000 boxes, there would be 50 people screaming online about what a piece of {censored} this box is. Put 100,000 in the field and you now have 500 people screaming in unison. That can be pretty loud. But does it mean there is a real problem?... only if you're one of those 500. It doesn't make it any less an issue for those 500, but that is what it is. But now to reduce that number, cost has to go way up. So now, you increase the weight and the price on 100% of the product to see a delivered quality reduction to 0.4%. Was it worth it? OK, so let's provide even more margin and reduce the incident rate to 0.3%, but now the cost to gain an additional 0.1% cost 10X what the first 0.1% reduction cost... now, is that worth it? Where's the line? That is up to JBL to decide. But I can tell you this; wherever it is, there will be someone on the wrong side of that line screaming about what a piece of {censored} that box is! Got it...I really need to take a class in Digital amp design.... I do appreciate the wealth of knowledge that yourself and Aged and others on this site have. Thank you all for taking the time to answer some of my screwed up questions... Link to comment Share on other sites More sharing options...
Members sibyrnes Posted December 6, 2012 Members Share Posted December 6, 2012 Originally Posted by Gypsy Kiss Got it...I really need to take a class in Digital amp design.... I do appreciate the wealth of knowledge that yourself and Aged and others on this site have. Thank you all for taking the time to answer some of my screwed up questions... If you do take that course, one of the first things you will learn is that in the world of pro audio, there is no such thing as a digital amp!Seriously, the "D" in class D does not stand for digital. Link to comment Share on other sites More sharing options...
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