BOOMMMM!!!
Hi,
Of course I agree.
I always design with a safety margin of at least 30 to 40% when it comes to caps.
If anyone would take a look at the Caesar circuit they could have predicted it easily.
Measured voltage is already a high 85 VDC,add to that the modulated AC signal voltage and you know that 100V insulation is not enough.
Any other cap would behave as described in above post.
One of the major problems with designer software is that it usually doesn't take dynamic conditions into account.
Cheers,
Hi,
Of course I agree.
I always design with a safety margin of at least 30 to 40% when it comes to caps.
If anyone would take a look at the Caesar circuit they could have predicted it easily.
Measured voltage is already a high 85 VDC,add to that the modulated AC signal voltage and you know that 100V insulation is not enough.
Any other cap would behave as described in above post.
One of the major problems with designer software is that it usually doesn't take dynamic conditions into account.
Cheers,
Re: CAP FEST
To the amp maybe. You could lose an eye if it happened while you were prototyping an amp without a chassis.
You could prevent this with a fuse in the cathode circuit.
BTW, the Nichicon cap failure I mentioned above was a short, not an explosion. It isn't only BG caps that fail this way!
fdegrove said:
To the amp maybe. You could lose an eye if it happened while you were prototyping an amp without a chassis.
You could prevent this with a fuse in the cathode circuit.
BTW, the Nichicon cap failure I mentioned above was a short, not an explosion. It isn't only BG caps that fail this way!
Frank, I respect your knowhow a lot but please think before you start the witch trial on BG ( which you have never even used before as you said in another thread ).
What do other caps do in the same situation ? I told you some of my experience and you seem to think only BG fails this way.
Caps sometimes short or open when failure happens and sometimes they even explode in the most extreme cases. A fact despite their safety vents and all the engineering that's behind the product to prevent it from doing so. At school we did the experiment with Philips caps. They blew as well.
So:
A) an expensive adventure is always a possiblity. Could be a cheap Nichicon that causes your expensive 300B to blow.
B) a freaking mess always occurs with this kind of failure. With BG, Elna, BCComponents or whatever brand / type.
C) For safety testing one Ceasar owner should try another brand and see what happens. I advise him or her to wear safety goggles with this experiment
These things happen. For instance I have a defective Pioneer DV-K101 here that has a IR3M03A 8-pin switching regulator used well below specs for creating a negative voltage from + 12 V. Current is no higher than 100 mA. Nevertheless this IC was probably made on a monday because it managed to burn the PCB and took the DAC with it... You know that a real 230 V switch costs too much nowadays for most manefacturers of equipment. So it failed and power was still on. Could have been my household that burned. Still I don't think all these regulators exhibit the same behaviour. Mine did.
What do other caps do in the same situation ? I told you some of my experience and you seem to think only BG fails this way.
Caps sometimes short or open when failure happens and sometimes they even explode in the most extreme cases. A fact despite their safety vents and all the engineering that's behind the product to prevent it from doing so. At school we did the experiment with Philips caps. They blew as well.
So:
A) an expensive adventure is always a possiblity. Could be a cheap Nichicon that causes your expensive 300B to blow.
B) a freaking mess always occurs with this kind of failure. With BG, Elna, BCComponents or whatever brand / type.
C) For safety testing one Ceasar owner should try another brand and see what happens. I advise him or her to wear safety goggles with this experiment
These things happen. For instance I have a defective Pioneer DV-K101 here that has a IR3M03A 8-pin switching regulator used well below specs for creating a negative voltage from + 12 V. Current is no higher than 100 mA. Nevertheless this IC was probably made on a monday because it managed to burn the PCB and took the DAC with it... You know that a real 230 V switch costs too much nowadays for most manefacturers of equipment. So it failed and power was still on. Could have been my household that burned. Still I don't think all these regulators exhibit the same behaviour. Mine did.
I RESPECT ANYTHING REALLY...
Hi,
Sorry if it seemed that way...no I don't want to haunt the BG in any way.
Still,I find it worriesome to see them behave like that and for safety's sake I only want to find out other manufacturer's product behaving the same way.
No more,no less.
Pls,read what I posted before and you will understand my concern.
Cheers,
Hi,
Sorry if it seemed that way...no I don't want to haunt the BG in any way.
Still,I find it worriesome to see them behave like that and for safety's sake I only want to find out other manufacturer's product behaving the same way.
No more,no less.
Pls,read what I posted before and you will understand my concern.
Cheers,
Hi Frank,
There is a possibility that the graphite particles in the BG's will conduct in case of using them over their maximum ratings.
I don't know. I reread tour posts and understand your concern very good. Maybe one user with such a shorted cap could send a mail to Jelmax Japan for more information on the matter of the shorting of the cap. I am still convinced that other types behave the same but maybe in a lesser degree. Reason for some concern as you stated correctly.
In the case that BG is "oversensitive" to exreme overvoltage one should always choose a cap with a very large margin, say 50 or even 100 % above the voltage that it normally sees. Is always wise to do. Comes to my mind a magazine once advised to choose the electrolytics max. voltage rating close to the actual voltage in that application. They probably didn't test BG that time.
Just think what Silmic ( with silk and hemp) or Cerafine ( with ceramics ) or OSCON ( "organic" stuff in it ) will do when exposed to extreme voltages ?!?!?
The smoke of the hemp in the Silmic's won't hurt for sure.
There is a possibility that the graphite particles in the BG's will conduct in case of using them over their maximum ratings.
I don't know. I reread tour posts and understand your concern very good. Maybe one user with such a shorted cap could send a mail to Jelmax Japan for more information on the matter of the shorting of the cap. I am still convinced that other types behave the same but maybe in a lesser degree. Reason for some concern as you stated correctly.
In the case that BG is "oversensitive" to exreme overvoltage one should always choose a cap with a very large margin, say 50 or even 100 % above the voltage that it normally sees. Is always wise to do. Comes to my mind a magazine once advised to choose the electrolytics max. voltage rating close to the actual voltage in that application. They probably didn't test BG that time.
Just think what Silmic ( with silk and hemp) or Cerafine ( with ceramics ) or OSCON ( "organic" stuff in it ) will do when exposed to extreme voltages ?!?!?
The smoke of the hemp in the Silmic's won't hurt for sure.
NO SILMIC HERE.
Hi,
Sorry to say so,I don't have any fancy PSU caps...
Once again,try to find your fellow countryman's mistake by looking at the circuit diagram.
Also find me a manufacturer of elcos with shorting plates under fault condition since this can easily set the house on fire.
That is my only worry now JP.
Cheers,
Hi,
Sorry to say so,I don't have any fancy PSU caps...
Once again,try to find your fellow countryman's mistake by looking at the circuit diagram.
Also find me a manufacturer of elcos with shorting plates under fault condition since this can easily set the house on fire.
That is my only worry now JP.
Cheers,
Not as much as a fire or electrical shock will degrade the listener...
Anyway, spending a day a year polishing fuses, holders and mains plugs is quite theraputic
Seriously Frank, put a fuse inline before the input to your transformer, it will cost about 3 Euro, and could save your, or someone else's life!
Fuse Protection
By all means, protect your investment with a proper fuse!
The fuse need not be in the signal path. In many designs, the shorted load will draw heavily upon the power supply. This must be fused.
A fuse poses little threat to the signal, as it is is a poor inductor, has very little resistance...and capacitance isn't an issue (unless you're amplifying RF, but that's a different situation).
My personal experience with power supply capacitor failures has been that the semiconductors will most assuredly protect the valuable fuses by blowing first. C'est la vie!
As your equipment ages, don't forget to make notice of the manufacturing date stamp on the electrolytics...and remember that keeping those cans cool is equally important as keeping the output devices cool! Old electrolytics must be replaced...especially if you are dealing with switching mode power supplies.
By all means, protect your investment with a proper fuse!
The fuse need not be in the signal path. In many designs, the shorted load will draw heavily upon the power supply. This must be fused.
A fuse poses little threat to the signal, as it is is a poor inductor, has very little resistance...and capacitance isn't an issue (unless you're amplifying RF, but that's a different situation).
My personal experience with power supply capacitor failures has been that the semiconductors will most assuredly protect the valuable fuses by blowing first. C'est la vie!
As your equipment ages, don't forget to make notice of the manufacturing date stamp on the electrolytics...and remember that keeping those cans cool is equally important as keeping the output devices cool! Old electrolytics must be replaced...especially if you are dealing with switching mode power supplies.
RE FUSE
Hi,
Pinkmouse,
I wasn't replying to your post in the fist place.
What you guys have overlooked IMO is that we are discussing a cathode bypass capacitor.
Moreover the expensive BG series that apparently short out when faulty.
Since I refuse to put a fuse there I was merely inquiring of other brands that are known to do this.
I don't think it is a common failure mode for caps.
Putting a fuse in a PSU for protection is another matter entirely and that is NOT under discussion here.
Steve,
Not so sure about that either.
Happy to you all too,
Hi,
Pinkmouse,
I wasn't replying to your post in the fist place.
What you guys have overlooked IMO is that we are discussing a cathode bypass capacitor.
Moreover the expensive BG series that apparently short out when faulty.
Since I refuse to put a fuse there I was merely inquiring of other brands that are known to do this.
I don't think it is a common failure mode for caps.
Putting a fuse in a PSU for protection is another matter entirely and that is NOT under discussion here.
Steve,
Not so sure about that either.
Happy to you all too,
After all these posts I still think it is in this particular Ceasar amp, Frank. I refuse to believe BG is the only one to exhibit this dangerous behaviour in this application. Till now there are no other reports about conducting BG's other than these !
BG is not known for this behaviour by other people than those 4 owners that have that error in their amp.
Unfortunately they are too expensive for destructive testing otherwise I would sacrifice one and feed it 10 to 15 V overvoltage and see what happens, only to stop this annoying witch trial. Reminds me of one of those birthdaystories of a relative that states that the Ford brand is unreliable because he had a Ford once in '67 that was unreliable.
Update: have heard some info on blown BG's in this amp because the bloody 300B of a certain brand was shorted internally and thus the BG received about 400 V DC and it may not come as a surprise that it started conducting.
In other words:there is a big chance the 300B caused the error.
Does having 'green eyes' distort one's vision?
Hi,
I must agree with all of jean-paul's comments.
All components will tend to fail if they are not used sensibly, i.e. within their ratings, and this may need to include a 'margin' for 'unusual' or non-anticipated circumstances.
Similarly, I would not use fuses to save cathode bypasses, since as Frank has suggested, they are sonically destructive in good sounding gear, and shouldn't be needed in a case like this.
In fact, I would not use fuses *anywhere*, either in my house wiring nor in my audio gear, unless absolutely *vital* from the safety aspect *and* there is no comparable circuit-breaker available which could be used instead. Simply put, fuses and the best possible sound, do not go hand-in-hand, unfortunately!
Also like j-p, coincidentally (and almost simultaneously!) in another thread about BGs, I made a plea for considerable care to be shown with the titles of new threads, which can be very misleading to the 'casual' observer.
Mud always seems to stick when it is thrown, and I thought these Forums were all about *advancing* knowledge for the benefit of the majority of readers, and not about 'having a go' at particular makes of components with which most of the commentators do not seem to have had any personal experience of.
As a direct result of very careful and fair comparisons, I now have a great deal of my 'audio budget' invested in BGs, because I know this makes sense from the point of view of good sound, but my experiences are restricted to about 2 years of their use in my own circuits.
I only finally accepted BGs disgraceful cost and ridiculous burn-in times, because (perhaps naiively-but only time will really tell!) the makers lead me to believe that their longevity should actually *exceed* the life of 'ordinary' electrolytics.
On seeing the title of Tomatito's thread (and I have already said, I'm sure he meant no harm), I immediately thought that I must have been over-optimistic and mistaken, and that all of a sudden BGs were failing all over the world!
Rather than this, seeing the true picture evolve over the last couple of days has made me realise that the make of cap has nothing to do with this issue, whatsoever, but there still seem to be a number of posters who insist on 'knocking' BGs, nevertheless, without having any relevant experience of them.
I am absolutely certain that in some months to come, many people will recall only part of the truth (even if they have read all through these later posts on the subject) and merely the heading will remain in their minds, that BGs are unreliable!
The simple fact that they have had no personal experience of BGs, together with probably not even reading carefully and fully about others' experiences, does not appear to deter these 'experts' from adding their own bit of embroidery to the tale, and so the myth is perpetrated and attracts credance!
Why people wish to be so negative and destructive I cannot imagine, but it reminds me in this instance of some acquaintances who tell me that (for example) Ferraris are lousy cars.
I know that they have never driven, nor even been a passenger in one, and they are merely attempting to convince themselves that their Fords, or whatever, are better, because that happens to be all they can afford!
I also cannot afford a Ferrari, but within my limited allocation for my audio hobby, I have free choice as to how it is allocated, and my choice has provided me with some very enjoyable results.
I have boxes of *all* of the usually-touted 'alternatives', which are going to waste (or sometimes I will now use them during development of a new circuit, before it is finalised), and much to my dismay and cost, I cannot convince myself that *any* of them in*any* location sound as good as the better (i.e. non-polar) BGs.
Notwithstanding their shortcomings in the way of costs and burn-in times, BGs cannot be beaten, as all of those who have *heard* them have so far said.
It also now appears that there is no *established* reliability or real safety issue, but they do clearly need to be used with sensible caution, even though possibly some other 'lesser- sounding' caps can be treated with more neglect.
I should, perhaps, also make it clear that I have no financial interest in BGs, nor in any of their suppliers.
Going back to my earlier analogy, I suppose it could be said that (if driven stupidly, i. e. outside of it's, or the driver's limitations) Ferraris are more dangerous than other cars, because they can go faster.
However, I would still dearly like the opportunity to have one of my own to drive, but if ever I was so fortunate, I would use similar caution and treat it with the respect it was due whilst driving it, as I do with the use of electronic components!
Regards,
Hi,
I must agree with all of jean-paul's comments.
All components will tend to fail if they are not used sensibly, i.e. within their ratings, and this may need to include a 'margin' for 'unusual' or non-anticipated circumstances.
Similarly, I would not use fuses to save cathode bypasses, since as Frank has suggested, they are sonically destructive in good sounding gear, and shouldn't be needed in a case like this.
In fact, I would not use fuses *anywhere*, either in my house wiring nor in my audio gear, unless absolutely *vital* from the safety aspect *and* there is no comparable circuit-breaker available which could be used instead. Simply put, fuses and the best possible sound, do not go hand-in-hand, unfortunately!
Also like j-p, coincidentally (and almost simultaneously!) in another thread about BGs, I made a plea for considerable care to be shown with the titles of new threads, which can be very misleading to the 'casual' observer.
Mud always seems to stick when it is thrown, and I thought these Forums were all about *advancing* knowledge for the benefit of the majority of readers, and not about 'having a go' at particular makes of components with which most of the commentators do not seem to have had any personal experience of.
As a direct result of very careful and fair comparisons, I now have a great deal of my 'audio budget' invested in BGs, because I know this makes sense from the point of view of good sound, but my experiences are restricted to about 2 years of their use in my own circuits.
I only finally accepted BGs disgraceful cost and ridiculous burn-in times, because (perhaps naiively-but only time will really tell!) the makers lead me to believe that their longevity should actually *exceed* the life of 'ordinary' electrolytics.
On seeing the title of Tomatito's thread (and I have already said, I'm sure he meant no harm), I immediately thought that I must have been over-optimistic and mistaken, and that all of a sudden BGs were failing all over the world!
Rather than this, seeing the true picture evolve over the last couple of days has made me realise that the make of cap has nothing to do with this issue, whatsoever, but there still seem to be a number of posters who insist on 'knocking' BGs, nevertheless, without having any relevant experience of them.
I am absolutely certain that in some months to come, many people will recall only part of the truth (even if they have read all through these later posts on the subject) and merely the heading will remain in their minds, that BGs are unreliable!
The simple fact that they have had no personal experience of BGs, together with probably not even reading carefully and fully about others' experiences, does not appear to deter these 'experts' from adding their own bit of embroidery to the tale, and so the myth is perpetrated and attracts credance!
Why people wish to be so negative and destructive I cannot imagine, but it reminds me in this instance of some acquaintances who tell me that (for example) Ferraris are lousy cars.
I know that they have never driven, nor even been a passenger in one, and they are merely attempting to convince themselves that their Fords, or whatever, are better, because that happens to be all they can afford!
I also cannot afford a Ferrari, but within my limited allocation for my audio hobby, I have free choice as to how it is allocated, and my choice has provided me with some very enjoyable results.
I have boxes of *all* of the usually-touted 'alternatives', which are going to waste (or sometimes I will now use them during development of a new circuit, before it is finalised), and much to my dismay and cost, I cannot convince myself that *any* of them in*any* location sound as good as the better (i.e. non-polar) BGs.
Notwithstanding their shortcomings in the way of costs and burn-in times, BGs cannot be beaten, as all of those who have *heard* them have so far said.
It also now appears that there is no *established* reliability or real safety issue, but they do clearly need to be used with sensible caution, even though possibly some other 'lesser- sounding' caps can be treated with more neglect.
I should, perhaps, also make it clear that I have no financial interest in BGs, nor in any of their suppliers.
Going back to my earlier analogy, I suppose it could be said that (if driven stupidly, i. e. outside of it's, or the driver's limitations) Ferraris are more dangerous than other cars, because they can go faster.
However, I would still dearly like the opportunity to have one of my own to drive, but if ever I was so fortunate, I would use similar caution and treat it with the respect it was due whilst driving it, as I do with the use of electronic components!
Regards,
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