In my search for new knowledge, did I visit one of my favorite YouTubers: learnelectronics and saw this video YouTube about super caps and batteries.
Many years ago did I here about some trying to build a battery powered "passive" preamp with an Elna stepper attenuator, and then did stupidity struck me! 🙂
Why not build an amplifier that uses two sets of caps, one set is being drained while the other set is being charged, and when empty, it switches caps-set. In that way would it work just like on batteries, totally floating from any mains.
I know sins I can think of it, hundreds of other may have got the same thought and decided it to be to stupid to use! So why is it a stupid idea? 🙂
Many years ago did I here about some trying to build a battery powered "passive" preamp with an Elna stepper attenuator, and then did stupidity struck me! 🙂
Why not build an amplifier that uses two sets of caps, one set is being drained while the other set is being charged, and when empty, it switches caps-set. In that way would it work just like on batteries, totally floating from any mains.
I know sins I can think of it, hundreds of other may have got the same thought and decided it to be to stupid to use! So why is it a stupid idea? 🙂
How much power does an amplifier draw ?
How much power can a 'cap bank' deliver ?
What sort of switching between the two (or more) banks would you use ?
What sort of power would this switch need to handle ?
How much noise would the switching and the charging circuit introduce ?
How much power can a 'cap bank' deliver ?
What sort of switching between the two (or more) banks would you use ?
What sort of power would this switch need to handle ?
How much noise would the switching and the charging circuit introduce ?
The answer to the second question is quite a lot, when you use models meant for regenerative braking in electric vehicles. See for example https://www.eaton.com/content/dam/e...rcapacitor-cylindrical-snap-in-data-sheet.pdf and SkelCap SCA Series Ultracapacitor Cells You will need many cells in series with some type of voltage balancing circuit, as each cell can only handle 2.5 V to 3 V.
What if it were build a bit like an UPS but with caps?
Yes super caps are unusable here, to low voltage, but what about in huge normal caps?
Hmm a 500W amp would be stupid, but what about a 25W or a 100W
Lets say 60V 10A maybe?
Just speculating here🙂
Yes super caps are unusable here, to low voltage, but what about in huge normal caps?
Hmm a 500W amp would be stupid, but what about a 25W or a 100W
Lets say 60V 10A maybe?
Just speculating here🙂
The problem with big caps is large current flow especially on power up.
A means of limiting current is required.
Most "standard" systems rely on transformer impedance to limit current.
A means of limiting current is required.
Most "standard" systems rely on transformer impedance to limit current.
Short answer: no.
Switching between different charge state caps (hense different voltage) is WAY WAY WAY worse that using a regular clean supply, so the idea is dumb.
Switching between different charge state caps (hense different voltage) is WAY WAY WAY worse that using a regular clean supply, so the idea is dumb.
This is a relatively old idea and has been successfully commercialised more than once.
Cannot imagine anyone with even a fleeting interest in audio not being aware 😎
Vinnie Rossi LIO review (Part 1 - Ultracapacitor power) | Darko.Audio
Cannot imagine anyone with even a fleeting interest in audio not being aware 😎
Vinnie Rossi LIO review (Part 1 - Ultracapacitor power) | Darko.Audio
“Even the best batteries like the LiFePO4 battery packs that we were using [for Red Wine Audio] are rated for around 2,000 cycles. Ultracapacitors will give you anything between 500,000 and 1,000,000 cycles. You would not need to replace them for the life of the product.”
I don't know what the lifetime of the product is supposed to be, but ultracapacitor lifetime specifications are usually something like 2000 hours at 65 degrees C, 10 years at room temperature.
Two problems immediately spring to mind.
1) Your supply rails will drop as the caps are slowly discharged.
2) There will be a nasty transient whenever you switch to the other set of caps since they will be charged to a higher potential.
As an alternative, it's not all that hard to design a very quiet power supply. If you're worried about ground loops, that's why Jensen transformers exist.
1) Your supply rails will drop as the caps are slowly discharged.
2) There will be a nasty transient whenever you switch to the other set of caps since they will be charged to a higher potential.
As an alternative, it's not all that hard to design a very quiet power supply. If you're worried about ground loops, that's why Jensen transformers exist.
Why capacitors? Why not batteries that have much more constant voltage and which could be intelligently switched between tracks?
And how do you get it "totally floating from mains" if there are switching devices or relays with leakage capacitance?
How is that any better than a mains transformer with grounded inter-winding screen?
And how do you get it "totally floating from mains" if there are switching devices or relays with leakage capacitance?
How is that any better than a mains transformer with grounded inter-winding screen?
I would not pursue this capacitor/battery idea, try instead investigating virtual battery and/or jlh ripple eater.
I think even i can live with the 0.01pF a large relay would have. Besides this is DC switching, so there is an extremely remote similarity to your transformer.
Apparently Vinnie has spend a bit longer than 5 min thinking about these issues 🙂
And neither is particularly problematic.
1) A non issue if you use regulators. A non issue for an amp where all biasing is done by a ccs. Slight and slow rail variation is unimportant.
2) Many possibilities here, none of them hard to implement. The many owners/reviewers of these amps offer sufficient testimony that no "nasty transients" occur.
No amp/preamp mains driven PS has ever been designed that remains immune to the effects of power cords and other mains related effects and this includes regenerator based supplies. Such a PS would be revolutionary. Still waiting.
Last edited:
What about if you recharge the caps at about twice the mains frequency? 😀
Perhaps you do not realize that in a regular linear power supply the caps are essentially "disconnected" from the mains except for the brief period during which they are being charged.
I have no idea why you are trying to create something without having a problem that will be solved by doing so. So, what is the "problem" that your battery/cap PS system would overcome? Maybe you should start there and think about it in a kind of cost/benefit way. You are introducing lots of switching (between caps) as they drain and must be recharged. This will cause switching transients on the supplies. That will be much like the charging pulses of a linear power supply... so what will be gained?
Perhaps you do not realize that in a regular linear power supply the caps are essentially "disconnected" from the mains except for the brief period during which they are being charged.
I have no idea why you are trying to create something without having a problem that will be solved by doing so. So, what is the "problem" that your battery/cap PS system would overcome? Maybe you should start there and think about it in a kind of cost/benefit way. You are introducing lots of switching (between caps) as they drain and must be recharged. This will cause switching transients on the supplies. That will be much like the charging pulses of a linear power supply... so what will be gained?
The switch over between banks happens at a much lower frequency than mains, perhaps once every few minutes. Using a smart circuit with current limiting it is easy to overcome any significant transient.
Apparently some people have no issues with mains power and hear no difference between amps powered directly from the mains vs amps powered from batteries. This thread is a complete waste of time for such people, yet they are inexplicably attracted 🙂
Apparently some people have no issues with mains power and hear no difference between amps powered directly from the mains vs amps powered from batteries. This thread is a complete waste of time for such people, yet they are inexplicably attracted 🙂
OP wanted to know if the principle was possible. He was told it was not and he was stupid to even ask. Then it turned out that it was not only possible but also a done deal.
For me the thread has run its course and i have better things to do.
For me the thread has run its course and i have better things to do.