Test WIIM pro+ with different power supplies

If we're talking about portable power banks, like the Samsung one posted above, in most cases they're using multiple Li-ion cells (the voltage of each cell varies from 4.2V to 2.8V as it discharges).
Also, the few ones I've disassembled have one thing in common: no room for large capacitors or heat sinks for linear regulators.
As such, I would say that if a power bank is portable then it's very likely to use dc-dc converters in a profit-oriented way.

I agree that one can build its own low-noise power supply but the final cost depends on the design decisions and the parts already owned.
 
A naïve question. In fact, how good is human hearing?🤔
A young person has, typically, better hearing than an elder. With age we lose hearing of the high frequencies.

Blind people, especially those, who have been born blind, tend to have exceptional hearing.

Musicians tend to have better hearing, at least a more realistic one. They know how the instruments sound in reality.

Everything is relative. The only fixed thing seems to be, that the human ear seems to be capable of hearing frequencies between 20Hz and 20KHz. In the best case...
 
Testing is good, great in fact, it just does nor cannot measure everything we can hear (or otherwise sense) but maybe someday gear will be invented than can do so. Humanity has a long way to go from here, we barely understand reality as it is, much more to learn:)

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Not sure I have written about this here but I have plenty of experience in test gear use as spent 20 years in the US Navy as first a Data Systems Tech then it was merged with Fire Control Tech and re-titled that. The most complex gear I worked on, one out of two left still in use, no training on it, cannot say to much but it had a large number of critical circuits that the block diagram was 20 pages long. The most important aspect took 4 scope probes to look at and if dialed in according to specs which was very difficult and hugely time consuming to do, the whole system did not work well and it was absolutely critical to the operation of the whole battle group. What did work, tuning it by ear, then it was so good we broke ever record of reliability by a far margin.

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I still have very good ears for being nearly 72 and my wife has better hearing than I do and she notices every change I make unless there is no change, she was an audiologist as well so has at least some experience in the field.

Rick
 
Nope, she has always been a civilian, I am now but but not for those 20+ years of servitude I was involved in most everything but subs, most of the time:)
 
If we're talking about portable power banks, like the Samsung one posted above, in most cases they're using multiple Li-ion cells (the voltage of each cell varies from 4.2V to 2.8V as it discharges).
Also, the few ones I've disassembled have one thing in common: no room for large capacitors or heat sinks for linear regulators.
As such, I would say that if a power bank is portable then it's very likely to use dc-dc converters in a profit-oriented way.

I agree that one can build its own low-noise power supply but the final cost depends on the design decisions and the parts already owned.
With surface mount components, size is minimal and with the lowish current draw of the devices used with these, heat sinking for the regulator may not be needed. The biggest expense for DIY supply would be the choice of battery capacity...LiFePO batteries aren't cheap but they are pretty much perfect for this usage.
 
With surface mount components, size is minimal and with the lowish current draw of the devices used with these, heat sinking for the regulator may not be needed.
The very way a linear voltage regulator works (opposed to a DC/DC converter) will require some sort of heat sink and smoothing cap, no?
 
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The very way a linear voltage regulator works (opposed to a DC/DC converter) will require some sort of heat sink and smoothing cap, no?
You always need a conversion from AC to DC before the regulator. One could have a 9 V SMPS 3A with DC output to feed a 5 V linear voltage regulator with a heatsink. This is how its done in many high end products. Every regulator has a certain voltage drop out , a linear needs a couple of volts.
 
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You always need a conversion from AC to DC before the regulator. One could have a 9 V SMPS 3A with DC output to feed a 5 V linear voltage regulator with a heatsink. This is how its done in many high end products. Every regulator has a certain voltage drop out , a linear needs a couple of volts.
My comment was regarding the use of power banks and if they might be using linear voltage regulators instead of DC/DC converters, not about how AC is rectified into DC. :)
 
My comment was regarding the use of power banks and if they might be using linear voltage regulators instead of DC/DC converters, not about how AC is rectified into DC. :)
Tough to say without tearing one apart...but I would say probably whichever one is cheaper. I was more focused on DIY a very simple totally linear approach. Maybe get around to try this later...after several other projects. Guess it's good to stay busy.
 
Using linear regulators means wasting some battery capacity to produce heat.
Unless the producer of a portable power bank brags about clean output voltage / suitable for audio equipments / something similar, it should be using dc-dc converters.

Of course, if someone finds a model with linear regulators, please let us know.
 
That LM3042 looks like a pretty kick butt IC. Very high specs. Data sheet has everything needed to DIY a supply.
 
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