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-   -   Shanti Dual LPS 5V/3A , 5V/1.5A (https://www.diyaudio.com/forums/vendor-s-bazaar/337859-shanti-dual-lps-5v-3a-5v-1-5a.html)

soundcheck 15th May 2019 09:05 AM

Ok. That looks better.

I usually account for about 20% headroom to be on the safe side.


PS are usually speced with continuous and peak power and overall wattage.
Would be nice to get all values listed for both outputs.

It would also be nice to see the output impedance.

Can you show us a datasheet?

Ripple, noise etc.

soundcheck 15th May 2019 09:32 AM

And.

The output voltage.

Is it straight 5V?

Many of us would appreciate a little headroom voltage to be able to feed
a 5V regulator. Something like 5.4V would normally do.
Can the outputs slightly be adjusted?

cdsgames 15th May 2019 10:18 AM

Quote:

Originally Posted by soundcheck (https://www.diyaudio.com/forums/vendor-s-bazaar/337859-shanti-dual-lps-5v-3a-5v-1-5a-post5791690.html#post5791690)
And.

The output voltage.

Is it straight 5V?

Many of us would appreciate a little headroom voltage to be able to feed
a 5V regulator. Something like 5.4V would normally do.
Can the outputs slightly be adjusted?


The voltage is in fact 5.1V. Since the beginning we designed it with some headroom You can slightly go higher at 5.2V with no hit on performance (by adjusting a small POT)

cdsgames 15th May 2019 10:20 AM

Quote:

Originally Posted by soundcheck (https://www.diyaudio.com/forums/vendor-s-bazaar/337859-shanti-dual-lps-5v-3a-5v-1-5a-post5791674.html#post5791674)
Ok. That looks better.

I usually account for about 20% headroom to be on the safe side.


PS are usually speced with continuous and peak power and overall wattage.
Would be nice to get all values listed for both outputs.

It would also be nice to see the output impedance.

Can you show us a datasheet?

Ripple, noise etc.


In about a week we will publish all data. We never took impedance readings , so we need to study. Still with the ultracaps right next to the DC wire output, it should be good.

cdsgames 15th May 2019 11:48 AM

If really necessary 5.4V , its possible to adjust the LDO by changing the R divider , but some soldering will be required

soundcheck 15th May 2019 12:33 PM

Quote:

Originally Posted by cdsgames (https://www.diyaudio.com/forums/vendor-s-bazaar/337859-shanti-dual-lps-5v-3a-5v-1-5a-post5791721.html#post5791721)
it should be good.

Come on CDSGAMES. This is no DIY hack. :rolleyes:

Some high quality devices clearly state impedance requirements.
Having the lowest possible ESR is not always a good thing.

The load heavily interacts with the supply and can even start oscillating.

This would be a nice read to see what I'm talking about.

cdsgames 15th May 2019 01:09 PM

We will measure.


However , we are talking impedance at around DC (low frequency) since the PSU is far from load and all HF decoupling must local (next to IC)


Impedance of our lytics + supercaps around DC is quite good (from datasheet)



This is why I am stating " "it should be good"


The output of Shanti is direct from supercaps + around 10.000uf of caps (a few in parallel). Further the active filter has a ESR of about 50mOhm and before that you have another 4500uF of capacitance .

soundcheck 15th May 2019 02:00 PM

Did you read the article?

It's not about good or bad. It's about matching the load.

As you've seen on Katana earlier. Alternating loads can modulate into the power rail,
causing severe noise through the backdoor.

It's always good to have a look at lab supplies e.g. this as reference.

You'll find a lot about transition times, slew rates asf asf. For a reason!

It's not about "good enough" or "trust me". It's about knowing what you're doing.

And there's a lot to gain for all of us.
Estimated 99% of the projects and findings over here at DIYA are based on trial and error experiences.

And that's IMO not good at all.

cdsgames 15th May 2019 05:25 PM

The paper you are referring to is referenced to a system with feedback . Our Nirvana has a feedback loop , only feedback on Shanti is on the LDO thats well behind output.


Shanti has been tested extensively with different loads manually , but we don't have specific machines to test with variable load.


At last , the way that we designed Shanti was to have full power on output. Even a load that changed from 0.5A to 3A in 10ms , will receive all electrons from output of Shanti . 1F =1V at 1A for 1second


Rest of Shanti power will slowly ramp up as supercaps + cap bank discharge .


So to summarize , Shanti does not have a real feedback loop. Peak power requirements are taken care by output supercaps + cap banks



I am yet to see such architecture in any LPS, but I am sure others will fallow.


It just makes sense.

cdsgames 15th May 2019 05:27 PM

Quote:

Originally Posted by soundcheck (https://www.diyaudio.com/forums/vendor-s-bazaar/337859-shanti-dual-lps-5v-3a-5v-1-5a-post5791839.html#post5791839)
As you've seen on Katana earlier. Alternating loads can modulate into the power rail,
causing severe noise through the backdoor.


Exacly . And how it was solved ? by adding capacitance on the last wire (after LDOs). Same for Shanti


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