KeithL
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Post by KeithL on Aug 10, 2021 12:55:35 GMT -5
Indeed... or at least late in posting my response... The XPA Gen3 amps do not have rail fuses... However there is one internal fuse - on the power supply. It is soldered in and is not considered to be "user serviceable" (it will also never blow under ordinary conditions). The XPA Gen3 amps are quite tolerant of power surges if they do encounter them... The only thing we can think of that could cause two of them to blow would be a sustained low voltage condition (or "brown out"). We've never seen this happen but it is not totally unexpected.
If the line voltage were to NOT shut off, but drop well below 100 VAC, and remain there for several seconds, it could cause the SMPS to draw excessive current. A similar situation could theoretically occur if the line voltage were to stick partway between the normal voltage ranges for 120 VAC and 230 VAC...
(This is a situation that most power companies try very hard to avoid since it is also very bad for devices like big air conditioners that have big motor-driven compressors.) If that's what happened then your amps really should come in for service. You’re a bit late to the party and really need to read the rest of the thread.
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Post by mgbpuff on Aug 10, 2021 13:46:30 GMT -5
Please provide empirical data to support your totally subjective “opinion”. Russ No. Do you own research.
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Post by audiosyndrome on Aug 10, 2021 19:28:03 GMT -5
Please provide empirical data to support your totally subjective “opinion”. Russ No. Do you own research. You missed my point. You stated SMPS = less reliability without any supporting evidence other than throwing out “more complexity and more parts”. A reader not knowledgeable in electronics might take that as the gospel even though your wrong. Yes, complexity and componentry affects reliability but much less so than the derating of the components used in the circuits. To demonstrate with a simple example: Capacitor C1 is hanging off the +15 volt rail and it’s rated at 15 volts. Capacitor C2 is hanging off the +15 volt rail and is rated at 35 volts. Capacitor C3 is hanging off the -15 volt rail and is also rated at 35 volts. Which combination of capacitors C1 (one capacitor running at full rated voltage) or C2 + C3 (two capacitors DERATED from full voltage by 57%) is more reliable? By your incorrect reasoning the answer would be C1 (less components). But the correct answer is C2 + C3 because of their derating. See MIL-HBK-217K for more info. By the way, the Benchmark ABH2 amplifier measured as well as or better than any other amplifier on the ASR website. Guess what, SMPS. Russ
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Post by mgbpuff on Aug 10, 2021 21:01:11 GMT -5
Obviously poorly engineered circuitry is going to fail first. Go away!
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Post by JKCashin on Aug 10, 2021 21:18:19 GMT -5
You missed my point. You stated SMPS = less reliability without any supporting evidence other than throwing out “more complexity and more parts”. A reader not knowledgeable in electronics might take that as the gospel even though your wrong. Yes, complexity and componentry affects reliability but much less so than the derating of the components used in the circuits. To demonstrate with a simple example: Capacitor C1 is hanging off the +15 volt rail and it’s rated at 15 volts. Capacitor C2 is hanging off the +15 volt rail and is rated at 35 volts. Capacitor C3 is hanging off the -15 volt rail and is also rated at 35 volts. Which combination of capacitors C1 (one capacitor running at full rated voltage) or C2 + C3 (two capacitors DERATED from full voltage by 57%) is more reliable? By your incorrect reasoning the answer would be C1 (less components). But the correct answer is C2 + C3 because of their derating. See MIL-HBK-217K for more info. By the way, the Benchmark ABH2 amplifier measured as well as or better than any other amplifier on the ASR website. Guess what, SMPS. Russ please stop confusing people with facts
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Post by mgbpuff on Aug 10, 2021 22:42:48 GMT -5
You missed my point. You stated SMPS = less reliability without any supporting evidence other than throwing out “more complexity and more parts”. A reader not knowledgeable in electronics might take that as the gospel even though your wrong. Yes, complexity and componentry affects reliability but much less so than the derating of the components used in the circuits. To demonstrate with a simple example: Capacitor C1 is hanging off the +15 volt rail and it’s rated at 15 volts. Capacitor C2 is hanging off the +15 volt rail and is rated at 35 volts. Capacitor C3 is hanging off the -15 volt rail and is also rated at 35 volts. Which combination of capacitors C1 (one capacitor running at full rated voltage) or C2 + C3 (two capacitors DERATED from full voltage by 57%) is more reliable? By your incorrect reasoning the answer would be C1 (less components). But the correct answer is C2 + C3 because of their derating. See MIL-HBK-217K for more info. By the way, the Benchmark ABH2 amplifier measured as well as or better than any other amplifier on the ASR website. Guess what, SMPS. Russ The Benchmark is a very unusual amp, designed by a partnership between two companies, Benchmark and THX. THX has perfected the technology to cancel out SMPS caused distortion by using a patented feed forward amp to compensate in real time. Apparently the same feed forward amp is also used to reduce crossover distortion. It has overhead problems and low gain which makes it a rather bland undynamic amp at any where near its rated continuous output. Also it costs $3000 vs the XPA $1000 or so. It's a very complicated amp. You are welcome to it. I'll stick with my XPA-1 Gen 1 amps. The XPA Gen 1 and Gen 2 remain the best amps ever made by Emotiva.
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Post by AudioHTIT on Aug 11, 2021 0:42:24 GMT -5
Obviously poorly engineered circuitry is going to fail first. Go away! Without data it’s still just an opinion and doesn’t further the discussion. What if you’re right, and the SMPS fails after 35 years, yet the linear / traditional lasts 40, but the life of other components in the amp typically fail at 30 years. Being right doesn’t make either PS a better or worse choice in this situation, and since heavy amps are more likely to be damaged in shipping, the SMPS is a better choice. This is of course a fictional what if, but just as plausible without data to back it up.
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Post by mgbpuff on Aug 11, 2021 6:32:00 GMT -5
So in the opinion of the moderator with no data to back him up, he is declaring that no subjective statement is ever anything more than opinion unless it is made into an objective statement with data to support. Given that stance, I see no reason for any of these blogs to exist because individual users of equipment not employed in the industry seldom have access to the kind of data you are requiring. Those that do, like KethL, also make statements without data to support. Claiming that you have the data, but not showing it, does not make your statement more valid. Whatever!!!!
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cawgijoe
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"We made too many of the wrong mistakes." - Yogi Berra
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Post by cawgijoe on Aug 11, 2021 7:10:56 GMT -5
I’m glad that Emotiva repaired the one amp and will likely repair the second amp. It’s unfortunate that this incident has left the OP with a sour taste for the product, but understandable. In my mind it had to be a surge of some sort that managed to overcome any defenses. Electricity can be strange. I had a modem go out years ago with a nearby lighting strike, yet all the other gear connected to my Panamax survived. I did replace the Panamax.
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Post by 405x5 on Aug 11, 2021 7:27:40 GMT -5
This thread made me think of ONE thing that would be COOL to have on my own high power amp. and perhaps these too for that matter…. A separate on board power switch for the power supply (whichever it may be) as the first step towards powering up after plugging in the amplifier. I’ve got a micro switch on the back that’s on/standby/off that I always use before plugging in after a storm or doing anything where the amp should have no power to it. Right now when I plug in, you can hear that HUGE power supply come to life and that rear switch keeps the juice from going any farther until I’m ready. The standby position enables the built in trigger I’ve always used with both the XMC1 and my prior processor. Have not had a reason so far to use the XMC triggers
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Post by AudioHTIT on Aug 11, 2021 9:20:55 GMT -5
So in the opinion of the moderator with no data to back him up, he is declaring that no subjective statement is ever anything more than opinion unless it is made into an objective statement with data to support. Given that stance, I see no reason for any of these blogs to exist because individual users of equipment not employed in the industry seldom have access to the kind of data you are requiring. Those that do, like KethL, also make statements without data to support. Claiming that you have the data, but not showing it, does not make your statement more valid. Whatever!!!! That’s a very valid point, and we are here to discuss both opinion and facts (the later being supported by data). I was implying, that opinions stated as fact lead to disagreement, that you don’t seem open to.
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Post by mgbpuff on Aug 11, 2021 9:36:45 GMT -5
So in the opinion of the moderator with no data to back him up, he is declaring that no subjective statement is ever anything more than opinion unless it is made into an objective statement with data to support. Given that stance, I see no reason for any of these blogs to exist because individual users of equipment not employed in the industry seldom have access to the kind of data you are requiring. Those that do, like KethL, also make statements without data to support. Claiming that you have the data, but not showing it, does not make your statement more valid. Whatever!!!! That’s a very valid point, and we are here to discuss both opinion and facts (the later being supported by data). I was implying, that opinions stated as fact lead to disagreement, that you don’t seem open to. Look the general statement that more complex circuitry with more components is more likely to fail than simpler circuitry with fewer parts is beyond opinionated. "Not necessarily" also applies, but reliability of more complicated circuitry is only increased by a greater attention to part specification, inspection, and validation along with burn in testing which may result in a more reliable product but at an increased expense in the final cost of that product. I don't need data to say such a thing, it is inherently a Platonic truism.
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Post by AudioHTIT on Aug 11, 2021 10:03:46 GMT -5
That’s a very valid point, and we are here to discuss both opinion and facts (the later being supported by data). I was implying, that opinions stated as fact lead to disagreement, that you don’t seem open to. Look the general statement that more complex circuitry with more components is more likely to fail than simpler circuitry with fewer parts is beyond opinionated. "Not necessarily" also applies, but reliability of more complicated circuitry is only increased by a greater attention to part specification, inspection, and validation along with burn in testing which may result in a more reliable product but at an increased expense in the final cost of that product. I don't need data to say such a thing, it is inherently a Platonic truism. Also valid, however I personally have had two ‘heavy’ (near 100 pounds) damaged in shipment, which has led me to the (experienced) opinion that heavy amps are ‘less reliable’ and I will no longer buy them (though I still own two). So looking only at circuit complexity doesn’t tell the whole story of an amplifier’s reliability (a variation on my original point). Now that we’ve learned that there is a PS fuse on the Gen3 amps, and that the OP may have experienced an unusual power condition, I’d be interested to know if the repair was more significant than replacing the fuse.
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Post by ttocs on Aug 11, 2021 10:09:07 GMT -5
HERE is a study of SMPS and the role capacitors play in failure rate. Translation to the English language seems to have suffered a bit, so please be understanding of the intent of the authors. Section IV if of interest here, and quoting: " Although the number of parts in control is more than power circuit, the failure rate of power circuit is more because of more stress and dissipation." It's of interest to me that they show why capacitors may be more prone to failure. Speaking to this they point to using multiple capacitors to reduce other detrimental effects, but which can then have a higher failure rate. I interpret this as a sacrificial design that in order to get a better quality circuit, longevity might be compromised.
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Post by mgbpuff on Aug 11, 2021 10:13:28 GMT -5
Look the general statement that more complex circuitry with more components is more likely to fail than simpler circuitry with fewer parts is beyond opinionated. "Not necessarily" also applies, but reliability of more complicated circuitry is only increased by a greater attention to part specification, inspection, and validation along with burn in testing which may result in a more reliable product but at an increased expense in the final cost of that product. I don't need data to say such a thing, it is inherently a Platonic truism. Also valid, however I personally have had two ‘heavy’ (near 100 pounds) damaged in shipment, which has led me to the (experienced) opinion that heavy amps are ‘less reliable’ and I will no longer buy them (though I still own two). So looking only at circuit complexity doesn’t tell the whole story of an amplifier’s reliability (a variation on my original point). Now that we’ve learned that there is a PS fuse on the Gen3 amps, and that the OP may have experienced an unusual power condition, I’d be interested to know if the repair was more significant than replacing the fuse. I apologize for being so bulldogish, BUT there is a breakdown in your logic; pointedly, shipping reliability and product reliability are two distinctly different issues. Now back to the problem at hand. I would be interested in the solution because I also had two Emotiva units fail after a loss of power event. Nothing else failed but two Emotiva Ultra 12 subs.
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Post by cubanjimbo on Aug 11, 2021 10:44:08 GMT -5
The XPA Gen3 amps do not have rail fuses... However there is one internal fuse - on the power supply. It is soldered in and is not considered to be "user serviceable" (it will also never blow under ordinary conditions). The XPA Gen3 amps are quite tolerant of power surges if they do encounter them... The only thing we can think of that could cause two of them to blow would be a sustained low voltage condition (or "brown out"). We've never seen this happen but it is not totally unexpected.
If the line voltage were to NOT shut off, but drop well below 100 VAC, and remain there for several seconds, it could cause the SMPS to draw excessive current. A similar situation could theoretically occur if the line voltage were to stick partway between the normal voltage ranges for 120 VAC and 230 VAC...
(This is a situation that most power companies try very hard to avoid since it is also very bad for devices like big air conditioners that have big motor-driven compressors.) If that's what happened then your amps really both need to be serviced. Thanks for this information. As I had stated earlier, the amps were NOT being used. They were both in their stand-by status. There may have been a short (1 second) brown out. If that power situation would cause both units that are not in use to fail, they are quite fragile.
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Post by 405x5 on Aug 11, 2021 10:46:36 GMT -5
Also valid, however I personally have had two ‘heavy’ (near 100 pounds) damaged in shipment, which has led me to the (experienced) opinion that heavy amps are ‘less reliable’ and I will no longer buy them (though I still own two). So looking only at circuit complexity doesn’t tell the whole story of an amplifier’s reliability (a variation on my original point). Now that we’ve learned that there is a PS fuse on the Gen3 amps, and that the OP may have experienced an unusual power condition, I’d be interested to know if the repair was more significant than replacing the fuse. If gear I like weighs A TON…..and I like it, I’ll buy it no matter what. In that regard your statement carries no weight (pun intended). These are long term durable goods and the dealer is responsible for safe arrival so…….
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Post by cubanjimbo on Aug 11, 2021 10:50:41 GMT -5
I’m glad that Emotiva repaired the one amp and will likely repair the second amp. It’s unfortunate that this incident has left the OP with a sour taste for the product, but understandable. In my mind it had to be a surge of some sort that managed to overcome any defenses. Electricity can be strange. I had a modem go out years ago with a nearby lighting strike, yet all the other gear connected to my Panamax survived. I did replace the Panamax. Thanks. I wonder if there is a way to tell if the Panamax unit is OK. It is amazing that despite having a Georgia Power surge protector at the power meter (with warranties on motor-driven units like the AC, refrigerator) and the Panamax unit, these two amps died. My other two amps from another manufacturer were also connected to another Panamax unit and they are fine. Not sure what type of power supply they use.
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KeithL
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Post by KeithL on Aug 11, 2021 11:06:00 GMT -5
It's an interesting paper - but it is a bit dated - and it makes an awful lot of assumptions. They basically made a general assertion - then chose a specific example to demonstrate how it "holds up in practice". This is perfectly valid - but you need a lot of background knowledge to put it in proper context.
For example, at one point, they mentioned "using multiple small capacitors to achieve a lower ESR". This is absolutely something that you can do. This is done in some designs - and, if you do it, it will produce the result that they say it will. You absolutely can parallel two or more capacitors, each with a relatively high ESR, to produce one combined capacitor with a higher capacitance value and a lower ESR. HOWEVER, you can also simply choose a single capacitor with a lower ESR instead. Which you choose will depend on the application, the relative costs, and the amount of space you have available.
It's also worth mentioning that the ESR is right on the spec sheet... and some capacitors not specifically sold as "low ESR models" actually have far lower ESR than others. And, of course, the ESR of the capacitors you use matters a great deal at some points in the circuit... But, in other places, the maximum sustained ripple current is what's critical, and the ESR doesn't matter nearly as much... And, of course, both of those vary with both temperature rating and operating temperature...
If I was grading their paper I would also bring up the fact that they neglected to say much (if anything) about the SWITCHING FREQUENCY. This wasn't that much of an issue when that paper was written... but it is today... Modern supplies can switch at anywhere between sub-20 kHz frequencies and multi-gHz frequencies (for modern gallium arsenide semiconductors).
And that is going to have a MAJOR impact on what capacitors are appropriate for use in what circuit positions...
If there is any real issue with SMPS, when compared to linear supplies, it is that SMPS are far more complex to design... And, because of this, especially in the early days, there were a lot of SMPS that simply weren't very well designed and didn't work very well... This was also true - long ago - for linear supplies... but many of us are too young to remember that.
(You're not missing much if you're too young to remember the smell of an overheating selenium rectifier...)
HERE is a study of SMPS and the role capacitors play in failure rate. Translation to the English language seems to have suffered a bit, so please be understanding of the intent of the authors. Section IV if of interest here, and quoting: " Although the number of parts in control is more than power circuit, the failure rate of power circuit is more because of more stress and dissipation." It's of interest to me that they show why capacitors may be more prone to failure. Speaking to this they point to using multiple capacitors to reduce other detrimental effects, but which can then have a higher failure rate. I interpret this as a sacrificial design that in order to get a better quality circuit, longevity might be compromised.
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KeithL
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Post by KeithL on Aug 11, 2021 12:17:45 GMT -5
Subjective statements are in fact opinion... However, contrary to what many people seem to believe nowadays, not all opinions are of equal validity or value... There is a big difference between "an educated guess" and, well, an uneducated guess.
There are in fact various degrees of credibility... for a variety of reasons. That is especially true in situations where technical knowledge is involved... Or, for that matter, where specific knowledge of any sort can reasonably be assumed... (For example, I've seen the pile of bent amplifier chassis in our scrap metal pile, while you have not...)
As to the weight issue...
We used to frequently see XPR and big XPA amps that were damaged in shipping... That includes units that were returned because they were damaged in shipping... And units that we serviced for other reasons that were damaged either on the way here or on the way back to their owners after service...
We actually lost so many XPR amps to shipping damage that we had to start shipping them on palettes... And that is one of the reasons we stopped offering out-of-warranty service on the XPR models...
And, in many cases, you could actually see how things got bent by the weight/momentum of that big heavy transformer... (Many shippers seem to think that the word "fragile" means "try not to drop more than two or three feet"... )
In contrast I've NEVER seen an XPA Gen3 amp whose chassis got bent by the weight of our new SMPS. (Although I don't see every repair that comes in... so there could have been one or two.)
I can also tell you that we very rarely get XPA Gen3 amps back for repair for power supply issues... (I don't have the specific numbers there... but we obviously take them into account for things like warranty coverage and pricing...)
If you want general statistical data you can probably find it via Google (or your favorite alternative search engine). You can also usually find manufacturer's specification sheets on many individual electronic components if you look.
Note, however, that technology evolves very rapidly these days. Therefore, something you read about "SMPS" or "Class D amplifiers", from even ten years ago, is probably already at least somewhat out of date.
(And anything much older than that is really ancient history.)
So in the opinion of the moderator with no data to back him up, he is declaring that no subjective statement is ever anything more than opinion unless it is made into an objective statement with data to support. Given that stance, I see no reason for any of these blogs to exist because individual users of equipment not employed in the industry seldom have access to the kind of data you are requiring. Those that do, like KethL, also make statements without data to support. Claiming that you have the data, but not showing it, does not make your statement more valid. Whatever!!!!
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