cowanrg said:could someone answer my questionor is it just too stupid to answer? is there an explaination or something im missing?
Hi cowanrg!
I there is no answer for this. Maybe, that can be an answer, probably:
When you make DIY, you select first the components. Many times you can not get the right component, what you want. Or you can get it, but on much higher price. So, when buying a capacitors (for me at least) the budget is limited, and the component availability is different.
And it is depend also on person too. Somebody fun of few big caps, somebody of many smaller. It is everybodies own choice. You have to test both.
So, I decide to compromise between my budget and component availability. Sometimes I use cap. banks, sometimes small capacitances.
But I think as a part of DIY philosophy you try to build the amp on cheaper way, and the price/sound value will be better. (Own working hours should not be calculated...)
An other point of view: you build up the electronics just for fun.
OK, it is not very close to your question, but some background.
So, there is not such a clear answer.
If cost is not an issue, buy BG caps for $200+ each...
For large cans needed a little bit more time for PS to load them, but have smaller ESR, smaller caps have higher ESR.
In my opinion PS caps can be:
for amplifiers small: 4700-6800uF
for amplifiers big: 10000-22000uF
You can read also Nelson's article about power supplies on Passlabs. Here you can find many informations.
But couple of articles available on Internet also. Try to investigate a little bit, you will learn a lot, I guarantie.
BR,
Milan
cowanrg
You want caps that will fit in the case you design. If you are using 24 x 4700uF pieces make sure that you can fit them in your case design. Nelson states that 100,000uF is a good amount of capacitance to insure a stiff supply in the power supply paper referenced above. If your case is only 3.5" tall, don't buy 4" x 4" caps.
Once the sizing issues are resolved, you next have to contend with the speed, cost and quality equation. Work out a budget for your capacitance needs. If your budget is $100 for caps look for caps that are less than $1/1000uF. The caps that Peter Daniel obtained represent a very good value not only from a cost per capacitance standpoint but also because the caps are fast. Caps with a higher VDC rating will generally make a better power supply. The other issue that ties into this is the type of amp you are building. An Aleph 5 will require nearly a 40V supply where an Aleph 3 requires less than 30V.
Another wrinkle in this equation is the way the caps are connected. Capacitors need to have good contacts and be solidly mounted. Bigger caps are heavier and less likely to oscillate. In addition bigger caps will have screw type mounting instead of solder points. The general consensus is that a good mechanical connection is better than most solder joints so a screw type connection will be more consistent. You may ask, why does the connection matter? It matters because of the ESR characteristics (parasitics) of the capacitor network. A lower ESR is preferable and is measured by the resistance, impedence and inductance of the capacitor network. Putting capacitors in parallel will reduce the impedence to a point but each parallel cap will increase inductance so there is a tradeoff point. Keep in mind that the more solder points you have to make in parallelizing caps increases the probability of inferior solder joints.
One last point, in choosing a form factor for a given capacitance, the taller cap will have a lower ESR than a shorter one. A 50000uF cap in a 5" tall x 3" wide form should have a lower impedence than a 4" x 4" form package only if the materials and quality are comparable. For example, a vendor offers a cap from the same family with two different sizes; the taller cap will have lower parasitics.
I hope this was helpful.
Here are the guiding issues on choosing power supply capacitors.
You want caps that will fit in the case you design. If you are using 24 x 4700uF pieces make sure that you can fit them in your case design. Nelson states that 100,000uF is a good amount of capacitance to insure a stiff supply in the power supply paper referenced above. If your case is only 3.5" tall, don't buy 4" x 4" caps.
Once the sizing issues are resolved, you next have to contend with the speed, cost and quality equation. Work out a budget for your capacitance needs. If your budget is $100 for caps look for caps that are less than $1/1000uF. The caps that Peter Daniel obtained represent a very good value not only from a cost per capacitance standpoint but also because the caps are fast. Caps with a higher VDC rating will generally make a better power supply. The other issue that ties into this is the type of amp you are building. An Aleph 5 will require nearly a 40V supply where an Aleph 3 requires less than 30V.
Another wrinkle in this equation is the way the caps are connected. Capacitors need to have good contacts and be solidly mounted. Bigger caps are heavier and less likely to oscillate. In addition bigger caps will have screw type mounting instead of solder points. The general consensus is that a good mechanical connection is better than most solder joints so a screw type connection will be more consistent. You may ask, why does the connection matter? It matters because of the ESR characteristics (parasitics) of the capacitor network. A lower ESR is preferable and is measured by the resistance, impedence and inductance of the capacitor network. Putting capacitors in parallel will reduce the impedence to a point but each parallel cap will increase inductance so there is a tradeoff point. Keep in mind that the more solder points you have to make in parallelizing caps increases the probability of inferior solder joints.
One last point, in choosing a form factor for a given capacitance, the taller cap will have a lower ESR than a shorter one. A 50000uF cap in a 5" tall x 3" wide form should have a lower impedence than a 4" x 4" form package only if the materials and quality are comparable. For example, a vendor offers a cap from the same family with two different sizes; the taller cap will have lower parasitics.
I hope this was helpful.
thanks you guys, that was very helpful. ive just never heard any discussion on the matter... amp design is talked about quite a bit, but power supplies seem to be looked over a lot.
well, to give background, im building aleph 2. i have commercial speakers that work very well with power. right now im at 320w x 2, but its just a class b (maybe) amp. they sound great. so, the aleph2 is the choice. im just researching EVERYTHING to make sure i get it done right.
im not your typical DIY person. i'm here really because i cant afford the equipment i want. when i saw one could build their own aleph, i was HOOKED! dont get me wrong, i love building and having the satisfaction of it being MINE, but ultimately, its all about the sound.
i will read the articles on pass' website and see what he has to say. just a couple more questions though, how do you tell the speed of the cap? can you do this with a high end multimeter? i have one that is pretty nice, sells new for around $500.
from what you both said, it seems like bigger caps are the way to go, if you get good ones, and if costs is little issue. i was looknig at black gate caps, they arent horribly expensive, and they are highly regarded.
so, is there a way to measure speed, or a way to measure impedance across a cap bank? (i imagine impendance could be measured easily, but not sure about the other).
thanks again!
well, to give background, im building aleph 2. i have commercial speakers that work very well with power. right now im at 320w x 2, but its just a class b (maybe) amp. they sound great. so, the aleph2 is the choice. im just researching EVERYTHING to make sure i get it done right.
im not your typical DIY person. i'm here really because i cant afford the equipment i want. when i saw one could build their own aleph, i was HOOKED! dont get me wrong, i love building and having the satisfaction of it being MINE, but ultimately, its all about the sound.
i will read the articles on pass' website and see what he has to say. just a couple more questions though, how do you tell the speed of the cap? can you do this with a high end multimeter? i have one that is pretty nice, sells new for around $500.
from what you both said, it seems like bigger caps are the way to go, if you get good ones, and if costs is little issue. i was looknig at black gate caps, they arent horribly expensive, and they are highly regarded.
so, is there a way to measure speed, or a way to measure impedance across a cap bank? (i imagine impendance could be measured easily, but not sure about the other).
thanks again!
well, aleph 2 sold for like $7K new. black gates are what, like $15 per? you need 4 per channel (just for power supply). i can deal with that. sure, i would really like to keep costs lower, but i really want this amp to sound the BEST it can. i dont want to skimp on anything.
Peter Daniel said:
I guess most of us are in that situation.
So you can't afford equipment, but you can afford Black Gates?
its not my first amp
my first big one, but not the first one ive made. will i be able to get decent priced caps that will perform very well? ive budgeted around $400 just for power supplies for monos. (considering the plitron transformers will cost like $120 each. so, that leaves a good amount of money for caps for the power supply. (wiring is a separate cost, so, the $400 is just for caps, transformers, and pc board if needed).
my first big one, but not the first one ive made. will i be able to get decent priced caps that will perform very well? ive budgeted around $400 just for power supplies for monos. (considering the plitron transformers will cost like $120 each. so, that leaves a good amount of money for caps for the power supply. (wiring is a separate cost, so, the $400 is just for caps, transformers, and pc board if needed).
You can check the Nichicon and Nippon Chemicon caps. M. Percy have large selection of Nichicon caps. Look around them.
Elna caps are not available very well, even they can be good caps too.
About capacitors speed: check the product datasheets. You can find really a lot of informations there.
Elna caps are not available very well, even they can be good caps too.
About capacitors speed: check the product datasheets. You can find really a lot of informations there.
Small, but mighty in numbers
I just bought these, Brand New! For $1 CAD each, I bought 40...gonna make 4 x 33,0000 Uf capacitor banks. Avg cost each $10....Sweet.
Anthony
I just bought these, Brand New! For $1 CAD each, I bought 40...gonna make 4 x 33,0000 Uf capacitor banks. Avg cost each $10....Sweet.
Anthony
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