You should not compare caps with different capacitance, as then the ripple current is not the same.
So let's take 39000uF 25V, with 12A ripple current at 50°C.
TS-UQ has a current ratio of 1.63, and about 60,000 hrs.
TS-HC has a current ratio of 2.07, and about 120,000 hrs.
So I guess in this particular case, it is worth using the 105°C cap.
The curves are taken from Krummer data sheets.
Not sure if they can be universally applied to all cap makes.
So use it with care.
Patrick
So let's take 39000uF 25V, with 12A ripple current at 50°C.
TS-UQ has a current ratio of 1.63, and about 60,000 hrs.
TS-HC has a current ratio of 2.07, and about 120,000 hrs.
So I guess in this particular case, it is worth using the 105°C cap.
The curves are taken from Krummer data sheets.
Not sure if they can be universally applied to all cap makes.
So use it with care.
Patrick
Thanks Patrick
I know what I will be using. I have seen enough capacitor failures to know that using 85 degree caps is asking for trouble. Anyway it was nice to see these graphs and to make sense of them.
I don't want to scare people off from using 85 degree caps though if you can get them for a good price.
If you can get the 85 degree caps for half the price of the 105 degree caps then I would get the 85 degree caps.
If not, my suggestion would be to get 105 degree caps.
I know what I will be using. I have seen enough capacitor failures to know that using 85 degree caps is asking for trouble. Anyway it was nice to see these graphs and to make sense of them.
I don't want to scare people off from using 85 degree caps though if you can get them for a good price.
If you can get the 85 degree caps for half the price of the 105 degree caps then I would get the 85 degree caps.
If not, my suggestion would be to get 105 degree caps.
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Contrary to your experience, I have no bad experiences with 85°C caps even in Class A amps running at 60°C heat sinks.
Especially, the ones I have from BC Components have retained their capacitance over the years very well.
In theory, there is a factor of 2 between 60,000 hours and 120,000 hours.
In practice I don't think my transistors will last 120,000 hours (which is 14 years continuous non-stop).
Of course you are all free to choose what you want.
I am not going to recommend any, other than good brands like Panasonic, BC, EPCOS, etc.
I have not tried Krummer, but they seem to be well received in German DIY forums.
Patrick
Especially, the ones I have from BC Components have retained their capacitance over the years very well.
In theory, there is a factor of 2 between 60,000 hours and 120,000 hours.
In practice I don't think my transistors will last 120,000 hours (which is 14 years continuous non-stop).
Of course you are all free to choose what you want.
I am not going to recommend any, other than good brands like Panasonic, BC, EPCOS, etc.
I have not tried Krummer, but they seem to be well received in German DIY forums.
Patrick
I have very rarely seen cap failures in amps period. Even in 30 year old amps, it seems to be the outputs and drivers that fail.
I wasn't specifically talking about amplifiers. For the record I have not had any type of amp failure (touch wood).
I was talking about electronic equipment in general. I am constantly getting lab equipment repaired and all of the cap failures have been 85 degree caps. None of the cap failures have been 105 degree rated caps.
Hence, this is the reason for my bias towards 105 degree caps.
I was talking about electronic equipment in general. I am constantly getting lab equipment repaired and all of the cap failures have been 85 degree caps. None of the cap failures have been 105 degree rated caps.
Hence, this is the reason for my bias towards 105 degree caps.
Looking at Euvl "Krummer" graphs, the important factor, that I see, is to keep the capacitors cool !
You do this by ensuring they are in the bottom of a well ventilated case and by ensuring that the applied ripple current is well below the maximum rated ripple current.
Doing both of these, you can expect quarter of a million hours of use from any temperature rated capacitor.
You do this by ensuring they are in the bottom of a well ventilated case and by ensuring that the applied ripple current is well below the maximum rated ripple current.
Doing both of these, you can expect quarter of a million hours of use from any temperature rated capacitor.
If those are the design criteria, then maybe you shouldn't be building Class A in the first place.
😉
Patrick
😉
Patrick
Lifetime model for Panasonic Snap-in's :
http://www.ndb.com.tw/files/panasonic/fj/FJ_LIFE計算公式.pdf
Patrick
http://www.ndb.com.tw/files/panasonic/fj/FJ_LIFE計算公式.pdf
Patrick
For all that remember post 550
Have a good Lough
Quote in full so not to confuse matters.
I have no problem with open technical arguments. You should know.
> Where you see volume content I am referring to pigment to binder ratio. There are also some level of volatile solvents (not included in the volume) which evaporate once applied.
That is cheating.
> However you can combine the two different types of particles in different ratios to get thixotropic flow properties as well as the benefit of high thermally conductive particles such as diamond.
> So you might end up with 20% diamond and 50% thixotropic particles.
That is exactly the same as what I meant by bi-modal.
If all particles are perfect spheres of the same size, and you can pack them by hand in the tightest possible manner, you can fill up about 65% of the volume. The rest of the space you can now fill up with a particle size (smaller spheres) about a factor of 10 smaller. Again if you have perfect packing, you would fill up say 50% of the remaining 35%, giving you a theoretical fill factor of 80%+.
That is theory. In practice, the particles are not spheres, they are not all the small size, and they do not pack themselves into perfect filling geometry. So a bi-modal mix will get you slightly above 70%. Extrusion is good for packing, compared to the like of isostatic pressing or slip casting, in that you have some lubrication effect of the molten plastic, plus the extremely high extrusion pressure which helps to pack the particles as tight as possible.
The Kerafol 82/86 is not the best they have in sheer thermal performance. I have tried other stuff which are better thermally. But they have such high filler content and hence so fragile that they break into pieces in your finger. So I thought I wasn't going to recommend the public to use any of those.
There are ways to get even better performance (e.g. doubling the pad size by soldering a 3mm copper plate to the TO247 of twice the footprint, and using a larger piece of Kerafol). But you need to know what you are doing. And at a dT of already 3°C (with the 2SK1530, so about 4°C for TO247), the gain is at most 2°C for all the trouble.
Patrick
There must be sometink wrong with 5mm cooper 3 apparently is much better as oviously capacitance dont count anymore.
Have a nice day
Al
Have a good Lough
Quote in full so not to confuse matters.
I have no problem with open technical arguments. You should know.
> Where you see volume content I am referring to pigment to binder ratio. There are also some level of volatile solvents (not included in the volume) which evaporate once applied.
That is cheating.
> However you can combine the two different types of particles in different ratios to get thixotropic flow properties as well as the benefit of high thermally conductive particles such as diamond.
> So you might end up with 20% diamond and 50% thixotropic particles.
That is exactly the same as what I meant by bi-modal.
If all particles are perfect spheres of the same size, and you can pack them by hand in the tightest possible manner, you can fill up about 65% of the volume. The rest of the space you can now fill up with a particle size (smaller spheres) about a factor of 10 smaller. Again if you have perfect packing, you would fill up say 50% of the remaining 35%, giving you a theoretical fill factor of 80%+.
That is theory. In practice, the particles are not spheres, they are not all the small size, and they do not pack themselves into perfect filling geometry. So a bi-modal mix will get you slightly above 70%. Extrusion is good for packing, compared to the like of isostatic pressing or slip casting, in that you have some lubrication effect of the molten plastic, plus the extremely high extrusion pressure which helps to pack the particles as tight as possible.
The Kerafol 82/86 is not the best they have in sheer thermal performance. I have tried other stuff which are better thermally. But they have such high filler content and hence so fragile that they break into pieces in your finger. So I thought I wasn't going to recommend the public to use any of those.
There are ways to get even better performance (e.g. doubling the pad size by soldering a 3mm copper plate to the TO247 of twice the footprint, and using a larger piece of Kerafol). But you need to know what you are doing. And at a dT of already 3°C (with the 2SK1530, so about 4°C for TO247), the gain is at most 2°C for all the trouble.
Patrick
There must be sometink wrong with 5mm cooper 3 apparently is much better as oviously capacitance dont count anymore.
Have a nice day
Al
The 2SK1530 has a pad size of 20.5x26mm, approximately 1.7 times that of a TO247 (16x20mm).
So to quote post #550 :
Standard Toshiba 2SK1530 = 44pF
2x TO247 footprint = 52p
A copper pad of 40x50 mm = 170pF
A copper pad of 40x36 mm = 122pF
Patrick
.
So to quote post #550 :
Standard Toshiba 2SK1530 = 44pF
2x TO247 footprint = 52p
A copper pad of 40x50 mm = 170pF
A copper pad of 40x36 mm = 122pF
Patrick
.
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I'm getting ready to buy toroids.
I'd thought of using the RC filtering as NP does in the F5. Initially I thought I could get away with 12V outputs in the toroid, but was advised to go higher. This thread has folks considering 15V outputs from the toroid.
What would be the right output voltage if one follows NPs PS ala F5? I was going to go with 500VA times two.
I'd thought of using the RC filtering as NP does in the F5. Initially I thought I could get away with 12V outputs in the toroid, but was advised to go higher. This thread has folks considering 15V outputs from the toroid.
What would be the right output voltage if one follows NPs PS ala F5? I was going to go with 500VA times two.
I don't understand the question.
Assume you want to use CRC (passive filter), what C and what R you intend to use ?
And what recitifier ?
Patrick
Assume you want to use CRC (passive filter), what C and what R you intend to use ?
And what recitifier ?
Patrick
Patrick, you know your circuit better than anybody else here...
Starting from the already mentioned 8 * 22 mF caps, what do you suggest for R and rectifiers?
Starting from the already mentioned 8 * 22 mF caps, what do you suggest for R and rectifiers?
I'm running blind. I'm not an expert on PS or any other circuit. I was going to use NPs F5 PS with a different out output voltage.
The Pass F5 PS uses 0R47 and 2.2K resistors.
Muy plan could easily be flawed. I liked NPs F5 PS because it was so simple to put together.
Assume you want to use CRC (passive filter), what C and what R you intend to use ?
And what recitifier ?
Patrick[/QUOTE]
The Pass F5 PS uses 0R47 and 2.2K resistors.
Muy plan could easily be flawed. I liked NPs F5 PS because it was so simple to put together.
Assume you want to use CRC (passive filter), what C and what R you intend to use ?
And what recitifier ?
Patrick[/QUOTE]
Assuming CRC, where C = 22,000µF.
I would use R = 0R68 (inductive, rated min 30~50W), to give a corner frequency of about 5Hz and continuous dissipation at 4A of 11W.
And probably STTH3010 for rectifier. But all a matter of taste.
Patrick
.
I would use R = 0R68 (inductive, rated min 30~50W), to give a corner frequency of about 5Hz and continuous dissipation at 4A of 11W.
And probably STTH3010 for rectifier. But all a matter of taste.
Patrick
.
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Patrick, why pick an hi voltage device such as the STTH3010 (quite high Vf) for a very low V application? Any advantage?
The second diode STTH2002D looks better IMO, but these diodes aren't specified as "soft recovery" anyway. A nice fatuature for audio.
What do you think about schottky? Paralleled MBR30H60 or H100 look nice: they're efficient and not expensive at all.
The second diode STTH2002D looks better IMO, but these diodes aren't specified as "soft recovery" anyway. A nice fatuature for audio.
What do you think about schottky? Paralleled MBR30H60 or H100 look nice: they're efficient and not expensive at all.
There are hundreds, if not thosands of diodes that will fit.
I only named the one I used to use.
You can also use STTH3002 which is low voltage (faster trr).
If you want soft recovery, you may consider MSR1560.
I never tried Schottky, so cannot comment.
Patrick
I only named the one I used to use.
You can also use STTH3002 which is low voltage (faster trr).
If you want soft recovery, you may consider MSR1560.
I never tried Schottky, so cannot comment.
Patrick
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