Super Caps?

Curious if any of the current regenerators use them, I think not?
What are the differences vs “regular” caps.

Reading about the NAGRA Classic PSU, for example, which touts the benefits of super caps. (It is considerably more expensive than even the P20, so not really comparable).

Super caps are more like batteries in some ways than caps: they can hold a lot more power per volume than a cap but they can’t be charged or discharged as fast as a cap. They have a more limited lifetime than a cap, but are more robust than a battery. In a lot of ways they are between batteries and caps.


Thank you Ted, interesting!
Connecting one of the Nagra super-cap PSUs into my P20 can only improve the sound, I would think? It would then feed an integrated Nagra DAC/preamp/headphone amp.

I don’t see why that wouldn’t work fine.


I suppose another difference is that a battery will provide complete isolation from the mains.
Although a PSA Regenerator feeding a supercap component I suppose is very close to complete isolation.
Generally, what can handle a faster current draw: a supercap or battery?

I have a full nagra HD setup with super caps. Preamp and dac work just fine with my p20. But I couldn’t make the power amp work. The p20 starts to hum very loud and thd out goes way up.

So, if you are staying with the low current devices (pre and dac), you should not face any trouble.

By the way, the HD line is really a piece of art.


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Hi, wow, very nice!

The HD Amp must have a killer power supply section.

I have the Tube DAC and just acquired a new MPS (with battery). I was going to get the Classic PSU (with supercaps) but since the P20 is feeding power, I didn’t think the noise reduction of the Classic would be noticeable, and it was about $10k more expensive.

I have a question about stacking the Nagra components. For the new HD line, they are meant to be stacked; but for the older HD or current Classic line, Nagra says not to stack the PSU (Classic or MPS), since it has a large transformer. Despite this, most photos show the components stacked.

In my case, I can only stack them. One reviewer complained of compressed dynamics and lack of inner detail when they were stacked; I can’t see how that could manifest itself? I would expect line noise when the volume is increased to high levels, if there was interference from the transformer. Anything else to check? I’m just concerned that I’m leaving some quality “on the table”, as it were!


Don’t think so. And I agree with you that it looks like overreaction it the reviewer. I just remembered that I have a friend with a tube dac + classic preamp + classic psi, all connected to a p10. He doesn’t stack the equipment.

But if you look close, the cabinets have little slots for stacking the equipment

Yes, you’re right, the cabinets have indents for the optional spike feet!

Perhaps others here can chime in on whether the proximity of an AC transformer can affect dynamics and “inner detail” (what does “inner” mean?!), without also causing a buzz/line noise?

Hi @tedsmith, curious to get your insight to this:
If you were feeding a DAC with a P20, which of these power supplies would you prefer for the DAC (or would all be equal):

  1. Super-cap
  2. Lithium Ion battery
  3. Linear power supply

Then the second part is if you could only power the DAC’s digital or analog circuits with (1) or (2) above, which would you choose?

I would say the battery is the best, but I’m not sure how fast the current draw is on a LiOn battery vs a super-cap?

A well filtered (and packaged) linear supply can have lower noise than a battery without a good filter. The logistics of charging the battery (or supercap) during long listening sessions aren’t trivial. You need to have multiple batteries and switch them between the charger and the load without adding noise…

I haven’t looked into batteries recently, but last I looked lithium iron phosphate (LiFePO4) batteries had a lot to recommend them. Safer than other lithium batteries and quick charge / low impedance.

I like supercaps in many ways, but the amount of run time per charge is significantly smaller than chemical batteries. If you have a good charger/load switch setup then that doesn’t matter as much.


As a side note Tesla will be rolling out next year the new generation of Powerwall 3. This is a cobalt free lithium iron storage battery.

2 posts were merged into an existing topic: We also love cars

For sure, let’s stick to Audio:
Does anyone know how much current draw an Lithium Ion battery can allow, vs. Supercaps or a linear PS?
My thought is that when your equipment demands it, does one power source excel over others?

Different lithium batteries have differing impedances. That’s one reason I liked LiFePO4 batteries, they were significantly better than others then. I’d guess that advances since then have altered the landscape. A linear supply can have a very low output impedance, batteries and supercaps not quite so low, but with proper regulation/bypass caps they all can provide for the needs of a low power device like a DAC. In general the instantaneous power available depends on your budget.


I forgot to ask the Real question, Ted, which is:
If you have a PowerPlant like the P20 feeding the DAC power supply, will a supercap or battery supply make a difference, over a standard linear power supply? Assume all 3 power supplies are “cost no object” designs.
To put it another way, is it worth investing in a supercap or battery supply if a P20 is feeding the supply anyway?

Nothing’s perfect and everything matters, another level of isolation is always good (ignoring budget). In this case you’d have that extra level of high frequency isolation from the other devices on the P20. I should also have been more clear, I was talking about DC output supplies. Your question isn’t well posed in that if the supercap or battery supply was external to the DAC it would have to have an AC output which may or may not be clean (usually you need “class d” to output AC from DC.) If you were talking about replacing the DAC’s internal power supply, then it’s more or less how much you want to spend much more than how the supply is implemented. Supercaps will cost more per amp of output and more for lower impedance. Batteries have a cost advantage over super caps. Linear power supplies are the least expensive, all other things being equal.

If you are using a DC supply and you have to move the batteries out of the DAC to a separate charger and the DAC (or whatever) is runs just from the battery (without a connection to any AC for any purpose) then you’d be getting real isolation (no groundloops, etc.) You’d still have to have a linear regulator from the batteries to the device and you’d be loosing a lot of power if the battery voltage is too much higher than the device needs.


Thank you, super grateful for your input.
"Your question isn’t well posed in that if the supercap or battery supply was external to the DAC it would have to have an AC output which may or may not be clean (usually you need “class d” to output AC from DC.) "
I’m referring to DC output supplies, like those made by Nagra. I think all of their current components have external DC output supplies. The linear supplies are stock, then they they upsell you on a LiIon battery supply, and a supercap supply (which replaced the battery supply). These are not cheap(!), so I’m curious if the difference would be noticeable, since all are being fed by a P20 anyway.

And the DAC has 2 separate outboard supplies: one for the digital section and one for the analog.
If you could only put the battery or supercap on one section, would you choose the analog?

I have no idea how well each of them is built. Usually companies only sell more expensive things if they make a good difference. I don’t think the technology is technically relevant, different technologies may make a difference in cost (but perhaps not in price) and in marketing, but you can make almost any technology work well with good design.

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