Has anyone looked at the Taiyo Yuden range of PAS super capacitors in relation to making a rather large Class A power amp capacitor block. They are available in 2.7 and 3.0 VDC ratings - but instead of paralleling them as you would normally do with other snap in types or lugged chassis mount caps that have the appropriate DC voltage rating, you wire them up in series to get the overall required DC voltage rating. You then must use balancing resistors across each cap to make sure they share the current evenly. There are tutorials on line to tell you how to work out the appropriate balancing resistor values for a given supply voltage. Nothing special in that at all.
I have made up a +/- dual rail PSU cap supply on matrix board using their 9 Farad / 2.7VDC rated super caps with a total of 12 caps in series per rail to give me 750,000uF (9 Farad divided by 12) at 32.4VDC rating for a "standard" +/- 25VDC PSU capacitor bank.
For those interested, these are only 12mm diameter and 20mm in height with a 5mm lead spacing, so you can end up with a very big supply in not a lot of space. Also good news is that these caps in more than 10 off quantity are only $2.91 USD each at Mouser and just slightly more at Digikey.
I will also use a soft start / mains DC blocker PCB to help with inrush current at switch on, in my next build which will be the MX2 using this cap bank.
For the technically minded, the standard Nelson Pass PSU design that has been posted in this forum on many occasions using 15,000uF caps with 4 in each +/- rail (60,000uF per rail) has an energy storage rating of 37.5 Joules at 25VDC nominal supply, whereas the above supply I am talking about has an energy rating of 468 Joules with an equivalent 750,000uF per rail at 25VDC rating, giving an energy rating of more than 12 times larger.
Also on the plus side, the cost differences between the 2 are quite large with a big saving using the super caps over conventional caps and also chassis space especially if someone did a properly laid out PCB for these caps. You could also then incorporate as many CRCRC or CLCLC type filtering options into the design that you may desire as you have a string of 12 caps in each rail to play with.
I would be very interested to hear other members thoughts on this proposal and even look forward to input from the master Nelson Pass himself as it might be an option for him to use in his First Watt commercial offerings into the future.
More info on these caps are available on the Taiyo Yuden website or via links to data sheets from the Mouser or Digikey product pages.
Gary..
I have made up a +/- dual rail PSU cap supply on matrix board using their 9 Farad / 2.7VDC rated super caps with a total of 12 caps in series per rail to give me 750,000uF (9 Farad divided by 12) at 32.4VDC rating for a "standard" +/- 25VDC PSU capacitor bank.
For those interested, these are only 12mm diameter and 20mm in height with a 5mm lead spacing, so you can end up with a very big supply in not a lot of space. Also good news is that these caps in more than 10 off quantity are only $2.91 USD each at Mouser and just slightly more at Digikey.
I will also use a soft start / mains DC blocker PCB to help with inrush current at switch on, in my next build which will be the MX2 using this cap bank.
For the technically minded, the standard Nelson Pass PSU design that has been posted in this forum on many occasions using 15,000uF caps with 4 in each +/- rail (60,000uF per rail) has an energy storage rating of 37.5 Joules at 25VDC nominal supply, whereas the above supply I am talking about has an energy rating of 468 Joules with an equivalent 750,000uF per rail at 25VDC rating, giving an energy rating of more than 12 times larger.
Also on the plus side, the cost differences between the 2 are quite large with a big saving using the super caps over conventional caps and also chassis space especially if someone did a properly laid out PCB for these caps. You could also then incorporate as many CRCRC or CLCLC type filtering options into the design that you may desire as you have a string of 12 caps in each rail to play with.
I would be very interested to hear other members thoughts on this proposal and even look forward to input from the master Nelson Pass himself as it might be an option for him to use in his First Watt commercial offerings into the future.
More info on these caps are available on the Taiyo Yuden website or via links to data sheets from the Mouser or Digikey product pages.
Gary..
> must use balancing resistors across each cap to make sure they share the current evenly
Share the Voltage, of course.
First "problem" is that audiophiles rarely run to new technology. Many cling to 1938. Others get into the 1970s. There IS bleeding-edge work, but not a lot.
I *was* startled to see how far SuperCaps have come. Once upon a time they had hundreds of Ohms of DCR. Today it is awful close to zero. I did apply a SuperCap to an old plan that loved huge capacitance. For that design, bigger caps turned out to be a bottomless pit; but that was different from your plan.
My wonder is: while DCR of one cap is very low, how big a stack do we need and what does that DCR add up to? But Twilight Zone is on and I don't care to do the math tonight.
Share the Voltage, of course.
First "problem" is that audiophiles rarely run to new technology. Many cling to 1938. Others get into the 1970s. There IS bleeding-edge work, but not a lot.
I *was* startled to see how far SuperCaps have come. Once upon a time they had hundreds of Ohms of DCR. Today it is awful close to zero. I did apply a SuperCap to an old plan that loved huge capacitance. For that design, bigger caps turned out to be a bottomless pit; but that was different from your plan.
My wonder is: while DCR of one cap is very low, how big a stack do we need and what does that DCR add up to? But Twilight Zone is on and I don't care to do the math tonight.
Spec sheet shows 1 amp maximum current.
Won't that be a problem for a class A power supply?
If the ripple current is less than 1 amp you hardly need a monster power supply.
This is related to the ESR issue that PRR mentioned.
The capacitors will overheat rather easily, there is a reason quality power supply capacitors are kind of bulky.
I wonder how the F1 cars do their KERS power supplies?
Best wishes
David
Cross post with PRR
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Thanks for that correction PRR - balancing resistors to make sure each cap shares the voltage equally.
like Papa said , when I asked him for opinion about using Eminence Alpha 15 in OB - "I like mine speakers having some magnet"
..... so , I like my caps having some current ripple capacity
..... so , I like my caps having some current ripple capacity
PAS0815LN2R7205 is 2.7V (up to 70C) and is rated <50 milliOhms when new.
2 Farad. $1.5 each.
Assume we need 40V operation. Allow 10% for mis-balance. We need 16 caps.
$24 for 125,000uFd 40V.
We have 0.8 Ohms total ESR. That's a lot compared to Al ecaps.
A random Al ecap is 100,000uF 40 VDC 8 mOhms for $61. 1/1000th the ESR!
Life-test for the SuperCap is based on 30 seconds charging at 1 Amp, 10,000 cycles, capacitance 70% of spec, ESR within 4X of the as-new spec (which was not outstanding). That's not much over an hour of loud playing.
So far not looking "better". The $$ is less but the ESR and ESR-life looks distressing.
I think these are still for "occasional" cycling, not line-frequency cycling.
2 Farad. $1.5 each.
Assume we need 40V operation. Allow 10% for mis-balance. We need 16 caps.
$24 for 125,000uFd 40V.
We have 0.8 Ohms total ESR. That's a lot compared to Al ecaps.
A random Al ecap is 100,000uF 40 VDC 8 mOhms for $61. 1/1000th the ESR!
Life-test for the SuperCap is based on 30 seconds charging at 1 Amp, 10,000 cycles, capacitance 70% of spec, ESR within 4X of the as-new spec (which was not outstanding). That's not much over an hour of loud playing.
So far not looking "better". The $$ is less but the ESR and ESR-life looks distressing.
I think these are still for "occasional" cycling, not line-frequency cycling.
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I was wondering if this would work.
If room in the enclosure allows you to, it may be possible to make a hybrid setup. Use Al caps as well supercaps! Like bypassing an Al cap with a ceramic, the low mOhm ESR of the Al caps will take the the of the work of supercaps so the supercaps can act like a battery storage.
If room in the enclosure allows you to, it may be possible to make a hybrid setup. Use Al caps as well supercaps! Like bypassing an Al cap with a ceramic, the low mOhm ESR of the Al caps will take the the of the work of supercaps so the supercaps can act like a battery storage.
Thanks guys for your responses, I thought there would be a down side, I might use the board I have made for a Kaneda line pre amp with +/- 15VDC supplies I want to do and use the traditional snap in caps for the power amps.
Besides the tech issues, they just look too small for a traditional NP Class A power amp!!
Besides the tech issues, they just look too small for a traditional NP Class A power amp!!
Be aware that a capacitor bank storing a huge amount of energy at low voltage can be almost as dangerous as a set of high voltage caps. Remove rings and other jewellery when working on it, as you could end up welding yourself to the caps.
Indeed. Don't wear metal jewellery when working with electric power. Consider induction, too. My electrician friend told me a story about a guy with a missing finger he was working with. When he inquired about it, he found out it was caused by a ring he was wearing while he walked near a large transformer. It became a shorted turn and burned his finger to the bone!
Hello,
If you don't need a high voltage you could try these.
BUT it will be like a short circuit if they are '' empty '' and connected to a typical power supply.
There are people who charge them with a current limited battery charger until they reach the desired voltage and then let the '' standard supply '' take care of supplying enough energy to keep the voltage at the same level.
Greetings, Eduard
P.s this one available at Mouser. You can find cheaper ones elsewhere but they might be bad.
If you don't need a high voltage you could try these.
BUT it will be like a short circuit if they are '' empty '' and connected to a typical power supply.
There are people who charge them with a current limited battery charger until they reach the desired voltage and then let the '' standard supply '' take care of supplying enough energy to keep the voltage at the same level.
Greetings, Eduard
P.s this one available at Mouser. You can find cheaper ones elsewhere but they might be bad.