10-Feb-2019, 07:47
I'm not trying to "shoot holes in theories" so much as simply to point out the fact that we don't have the kind of evidence of what's happening at the moment the fault triggers which would enable us to say that it's one thing or another. The bug is definitely a possibility for the cause but it's not the only possibility. What I'm saying is that we don't have sufficient evidence to say it's any particular one of the possibilities that is causing it.
Pim says "it would have to be a pretty precise voltage peak to land exactly between the two 'sensitivity points' of the two individual amps" but without knowing what the tolerances applying to the protection circuit are, we don't know how precise the peak would need to me to land exactly between the trigger points for the 2 amps. If the tolerance is +/- 0.5 Volt, the range between the trigger points could be up to 1 V, if it's +/- 1 V then that range becomes 2 V and so on. There may well also be a time related component to the trigger, the spike may need to last for a certain number of milliseconds and that component of the specification may also have tolerances.
There's an old gag line which goes something like "I don't know what's going on but I haven't got any information to base that on". That's the kind of situation we're in. What new need is more information and part of that "more information" is reliable information about the voltage at the exact moment the fault triggers. Another part of that "more information" that we could use is more reports. It's harder to work out what's going on when all we have is a few sporadic reports rather than the frequent and regular reports we were getting over a year ago.
As I said, I had the fault about 10-12 times before I got the CI board upgrade which occurred around 10-11 months after I got my 140 so that's 10-12 faults in 10 to 11 months, say a fraction over once a month. It's now 11 months since I got the upgrade and I've had it only once since then and that one time occurred before I started using voltage regulation. The fact that I haven't had a fault in the 2 and a bit months I've been using voltage recommendation doesn't necessarily mean anything and the fact that AlexS has had it once since starting to use voltage regulation doesn't tell us much either in some ways but it definitely does muddy the water a little more. One of the things I was told when I was having to design and conduct a research project when I was doing my postgrad qualification in health and safety is that "you can't prove anything with a sample of 1". That's not quite true, a sample of 1 can prove or disprove some things but it certainly isn't enough to prove that a fault several people are experiencing has a single specific cause when there's 2 or more possible causes and we should actually see the shutdown and get this error message if a particular situation occurs.
I think we can definitely say something has changed with the CI board upgrade, both because I've had the problem significantly less frequently since then and also because reports generally have dropped in frequency since then. The one thing we can be sure of is that it's going to be harder to pin the cause down now because the frequency of the fault has dropped so much. If you want to start testing an amp and tracking incoming voltage against when the fault occurs, you only need a dozen amps and a month or so to get data on a dozen faults but if the incidence has dropped to once a year then you'd need a dozen amps and a year of so to get the same amount of data. Faults that occur frequently are a lot easier to identify and solve than faults which occur very infrequently.
Pim says "it would have to be a pretty precise voltage peak to land exactly between the two 'sensitivity points' of the two individual amps" but without knowing what the tolerances applying to the protection circuit are, we don't know how precise the peak would need to me to land exactly between the trigger points for the 2 amps. If the tolerance is +/- 0.5 Volt, the range between the trigger points could be up to 1 V, if it's +/- 1 V then that range becomes 2 V and so on. There may well also be a time related component to the trigger, the spike may need to last for a certain number of milliseconds and that component of the specification may also have tolerances.
There's an old gag line which goes something like "I don't know what's going on but I haven't got any information to base that on". That's the kind of situation we're in. What new need is more information and part of that "more information" is reliable information about the voltage at the exact moment the fault triggers. Another part of that "more information" that we could use is more reports. It's harder to work out what's going on when all we have is a few sporadic reports rather than the frequent and regular reports we were getting over a year ago.
As I said, I had the fault about 10-12 times before I got the CI board upgrade which occurred around 10-11 months after I got my 140 so that's 10-12 faults in 10 to 11 months, say a fraction over once a month. It's now 11 months since I got the upgrade and I've had it only once since then and that one time occurred before I started using voltage regulation. The fact that I haven't had a fault in the 2 and a bit months I've been using voltage recommendation doesn't necessarily mean anything and the fact that AlexS has had it once since starting to use voltage regulation doesn't tell us much either in some ways but it definitely does muddy the water a little more. One of the things I was told when I was having to design and conduct a research project when I was doing my postgrad qualification in health and safety is that "you can't prove anything with a sample of 1". That's not quite true, a sample of 1 can prove or disprove some things but it certainly isn't enough to prove that a fault several people are experiencing has a single specific cause when there's 2 or more possible causes and we should actually see the shutdown and get this error message if a particular situation occurs.
I think we can definitely say something has changed with the CI board upgrade, both because I've had the problem significantly less frequently since then and also because reports generally have dropped in frequency since then. The one thing we can be sure of is that it's going to be harder to pin the cause down now because the frequency of the fault has dropped so much. If you want to start testing an amp and tracking incoming voltage against when the fault occurs, you only need a dozen amps and a month or so to get data on a dozen faults but if the incidence has dropped to once a year then you'd need a dozen amps and a year of so to get the same amount of data. Faults that occur frequently are a lot easier to identify and solve than faults which occur very infrequently.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.
Brisbane, Qld, Australia
