Electronic Engineering and hi-fi set-up

[Miska]

11 hours ago, Arpiben said:

 

Completing your reference some measurements. Not all batteries are equal vs noise...

http://www.hoffmann-hochfrequenz.de/downloads/NoiseMeasurementsOnChemicalBatteries.pdf

 

...and once you use battery, the output voltage range and stability is not likely what you need... So in most cases you have DC-DC converter connected to the battery to produce useful voltages. Which is essentially an SMPS...

 

[Miska]

7 hours ago, Kal Rubinson said:

That doesn't make any sense to me.  If the source of the noise is inside the device, neither should affect it.  If it exists with the PS, it or the AC line is the culprit.  The battery (assuming it is adequate to the load) should not introduce any.

 

Use of battery just requires different kind of surrounding electronics which is another source of problems.

 

For example many battery power banks used to provide USB charging voltage are noisy as hell thanks to cheap ass DC-DC converter / switching regulator needed for the task. (using a linear regulator with a power bank would be immensely stupid because it would waste lot of precious electricity into heat)

 

[Miska]

4 hours ago, Ralf11 said:

it might be fruitful to give DIYers some guidelines on what battery type & capacity, etc. would allow them to power a DAC without any conversion or 'surrounding' electronics...

 

Problems are that battery cells have some inherent per-cell voltage, so battery pack voltage is some multiple of that. In addition, battery voltage is not stable but also depends on charge level and load. In addition, it is good to have some protections for things like short circuits and such so that there's less risk of fire and explosions. Car batteries don't have such, as they need to supply few hundred amps of current for short periods...

 

In addition batteries have various other properties, for example car/starter batteries don't like deep discharge and get bad very quickly if you discharge them more than about 50%. There are then auxiliary power lead-acid batteries (nominally 12V and 24V) that are designed for boats and motor homes to supply power for lights and such, these are built to persist deep discharges, but cannot supply as much current. If your battery voltage reaches 12V, it is pretty empty already and at about 11.5V it is out.

 

Li-Ion cells are more sensitive beasts than lead-acid batteries, so you need to be more careful how you deal with those...

 

But overall, batteries are one of the subjects where you could write several books worth of technical story..