The amp that didn't explode! Yet!

[jkeny]

yea i think there overcomplicating it
switching between charge and discharge seems like a real pain
if the caps cant function 'as good' in a normal simultaneous charge/discharge situation
im really not seeing the point

I've seen this mistaken thinking before - they think that simultaneously charging a Lifepo4 while powering circuit from it is going to let noise through to circuit so they think they need to completely isolate power to circuit from mains charging.

Charging ultracaps & powering circuit from them simultaneously is the way to use these & it's far, far simpler than this 'purist' approach they are trying but you can see from the posts in that thread that many would buy such a 'purist' solution!!

if that uptone ps has regulation post caps, surely going to seriously inhibit potential?

You have to have regulation on the output as the ultracaps don't have the capacity of a battery so within a couple of seconds of power draw, an ultracap will start to output a lower voltage & this is with low current draw of DAC (<0.5Amp) - trying to power an amplifier in this manner is bound to fail or be hugely complex & costly.

Yes, typical EE thinking goes for low noise Vregs & raves about the sound until they compare to LifePo4 - it's not just about low noise

[nige2000]

multiple bruteforce charging regulators could work in more demanding applications like class a amp
will be just as expensive as batteries id assume but maybe a little simplier

[jkeny]

multiple bruteforce charging regulators could work in more demanding applications like class a amp
will be just as expensive as batteries id assume but maybe a little simplier

I'm not sure - I think the main advantage of LiFePO4 batteries is their huge current output so whatever sudden current demand from the circuit is met by the stored charge in the battery without the charger being involved - it's like a large water storage tank being filled at the top by a trickle of water & a tap at the bottom satisfies any dynamic water demand without the water filler at the top being involved. In other words LiFePO4 batteries are almost completely immune to the quality of the charging circuit

Ultracaps/supercaps are not like this - they drain much quicker & the water flow out of the bottom of the tank gradually reduces as the tank is emptied.

I think the charger comes into play much sooner with ultra/supercaps so we are back to just having a large capacitor on a charger PS

[nige2000]

multiple bruteforce charging regulators could work in more demanding applications like class a amp
will be just as expensive as batteries id assume but maybe a little simplier

I'm not sure - I think the main advantage of LiFePO4 batteries is their huge current output so whatever sudden current demand from the circuit is met by the stored charge in the battery without the charger being involved - it's like a large water storage tank being filled at the top by a trickle of water & a tap at the bottom satisfies any dynamic water demand without the water filler at the top being involved. In other words LiFePO4 batteries are almost completely immune to the quality of the charging circuit

Ultracaps/supercaps are not like this - they drain much quicker & the water flow out of the bottom of the tank gradually reduces as the tank is emptied.

I think the charger comes into play much sooner with ultra/supercaps so we are back to just having a large capacitor on a charger PS

I'd be curious, maybe the tank only has to be a certain size
Maybe esr plays a bigger part in combination with capacity

Though not sure if I'm so curious I'll run out and buy 20 of these supercaps

[jkeny]

I'd be curious, maybe the tank only has to be a certain size
Maybe esr plays a bigger part in combination with capacity

Though not sure if I'm so curious I'll run out and buy 20 of these supercaps

Yea, Abrax experiments with large banks of ordinary electro caps seemed to suggest that ESR + capacity are significant factors but then we often use batteries with wires which cause higher inductance & negate some esr advantage - so go figure?

You know you're going to buy 20 of these, don't you!!

[abraxalito]

I've seen this mistaken thinking before - they think that simultaneously charging a Lifepo4 while powering circuit from it is going to let noise through to circuit so they think they need to completely isolate power to circuit from mains charging.

For common-mode noise this is true - isolation is one way to reduce CM noise. For normal mode noise of course its rubbish. I guess the purpose of swinging cap banks is CM noise reduction but the switches used are going to have some capacitance across them which limits the rejection in practice.

[jkeny]

I've seen this mistaken thinking before - they think that simultaneously charging a Lifepo4 while powering circuit from it is going to let noise through to circuit so they think they need to completely isolate power to circuit from mains charging.

For common-mode noise this is true - isolation is one way to reduce CM noise. For normal mode noise of course its rubbish. I guess the purpose of swinging cap banks is CM noise reduction but the switches used are going to have some capacitance across them which limits the rejection in practice.

With my battery powered devices there is no discernible difference between running solely off battery or from battery with charger attached. I'm not sure I undertake what you are saying?

I also wonder if cm noise is more common than thought judging by the number of people on computer audiophile reporting improvements with using cat 7/8 cable as dc power cable or is something else at play?. Our own Pearse is one of those.

[Sligolad]

That whole Cat7/Cat8 rabbit hole really opened my eyes to the big impact of DC cables so definitely something weird going on there.
The effect is not subtle but easy to hear by just a quick swap of cable, bit like the MLC versus SLC SD Card effect.
Lower frequencies really open up and you get a real feel that the volume has increased when you make the change.

Do not think i will be testing them in "the amp that did not explode yet" though :-)

[jkeny]

Yes, interesting, Pearse - it seems to be the same effect as battery power - have you tried these DC cables with battery power - did it make any difference?

[abraxalito]

With my battery powered devices there is no discernible difference between running solely off battery or from battery with charger attached. I'm not sure I undertake what you are saying?

Absence of discernable difference I wouldn't have thought counted as absence of CM noise. CM noise might not strongly affect the particular equipment you were using for example. Generally its worse when one or more of the mains PSUs is a switcher as pretty much all SMPSUs contain CM aggressors. If they're all 'linear' then there's a noise loop but the current in the loop depends on external factors.

I also wonder if cm noise is more common than thought judging by the number of people on computer audiophile reporting improvements with using cat 7/8 cable as dc power cable or is something else at play?. Our own Pearse is one of those.

I'm still puzzled by that - no-one yet AFAIK has A/B'd with a completely isolated (battery) supply to see if the improvement effect is the same.