Hello
going to bend a project with raspberry pi4 streamer, which power supply is preferable, seems like many people use linear power supplies?
or is there a ready-made solution for this, at least to bend with
then maybe build into the case ?
is it better with linear, how is the switched power supply otherwise?
For a rPi linear outruns a switched psu. Mainly becase there is almost non filtering on a rPi.
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Can these work? to a solution in the beginning?
neither of those two meet the minimum requirements for an rpi4.
all though the first one may be fine as long as you dont have anything power hungry connected to the usb.
Ideally the recomended PSU specs for rpi4 are 5 Volts 3 Amps.
Where are the specs for that at 5V doesnt state the current.
But Looking at the inside, its using a 12 volt transformer, the losses will be huge at 5 volts be lucky if it could supply 1.5A before over heating
I think it does:
Just ran a test on a rPi5 with this supply, for the complete boot sequence.
Min Voltage = 5.144VDC, MAX Voltage = 5.152. So a delta (load regulation) of 8mV on a rPi5.
hmm …It cannot be using the 12v tranformer that is pictured then.
Have you opened yours up. What tranformer is inside.
And offcoarse Volumio has it’s own PSU:
Yeah I commented on that further down.
The one with the 9v transformer would be getting to its max capacity at 5 Volts with around 2 Amps and getting really hot if you pushed it any further.
The 7V one would top out at about 2.6A
Thanks, for all the answers, sounds like it requires a little more than I had expected from the beginning, also saw this one?
otherwise if maybe easier to make your own Linear power supply, as long as you know how much power is needed, firstly for raspberry4 then for dace and last but not least a screen must be connected
Not sure how you can do a quick calculation combing the TL431, C8550 and IRF9Z34. I have two of them and one powers 2 rPi4’s (egg boiler version) and the other the rPi5. With a load regulation of 8mV they do their job.
Or you can build one yourself (from: Vincent_Fong):
Remembering what I was taught at college a long time ago lol
What regulators being used have little to do with it other than obvously keeping the voltage drop to a minimum, better the regulater bettter they are at keeping the level correct. Which it seems like the are doing very nicely
Regulators also have to dispose of the unused power (Heat), this is how true linear power supply works.
roughly…
The egg boiler 
The Transformer design power is 25W that wont change
9V RMS AC rectified voltage = 9 x 1.4 = 12.6 V DC
12.6V - 5V = 7.6 V ( this is what the regulator throws away, the wattage will vary depending on current draw)
So at 3 Amps load
(5V x 3A ) + (7.6V x 3A)
15W + 22.8W = 37.8W which is the power being pulled from that poor 25W transformer…
With some deductive maths you can work out the max power it can supply with out going over the design power of the transformer.
You may be getting away with it because the pi draws very little when running volumio, but you are very close to the edge.
Have you ever seen what a mess an encapsulated transformer makes when it goes up.and the smell…jees its like beeing in a smoked fish factory
Out of curiosity I looked up the the componants you listed only one is a regulator, one is a high speed switching transistor, and the other is a power mosfet which I assume is the final output control.
Not sure if there is some Chinese trickery going here being disguised as a linear PSU.
Who knows
Have you actually tried to see if it will give 3.5 amps at 5v.
This is also often praised
keep in mind that a MOSFET (IRF9Z34) ain’t a regulator.
The TL431 combined with the resistors provides the output voltage, the MOSFET provides the current.
(If I recall it correctly as this was also many moons ago, for me)
You are missing the point, its not the regulator side thats the problem the specs of that power mosfet are sufficient to handle the current drawn.
Remember true linear regulators do not work like a switch mode type, a true linear regulator disposes of the unused power as heat. This is just how they work. Not very efficient
If it is setup as a true linear regulator at 5V 3A it will still be dissipating 22W as heat. ( No problen for the regulator) That is 22W of wasted energy which the transfomer still has to supply out of a budget of 25W. Simply does not leave enough
So… The problem here is the transformer being underrated (incorrectly specced) for the job.
The maths are above. Have I worked it out wrong ?
Have you tested the PSU at the rated 3.5A load ? Does it deliver for a sustained amount of time with out over heating.
Linear power supplies are a waste of money in almost all cases.
If you’re worried about noise, either transmitted or conducted, know first that by far the main source of noise in any PSU/Pi combination is the Pi because it’s a poorly shielded high frequency device and an active source of relatively high powered multi-frequency interference.
To control transmitted (over the air) noise, put the Pi in an aluminium case and ensure the case is grounded for example by using metal standoffs.
To prevent conducted noise, particularly mains frequency ground loop noise, use digital outputs that are intrinsically resistant to conducted noise and eg a USB isolator (pay no more than $10) or other ground isolation device, which is basically a small 1:1 transformer on the ground connection between the Pi and the audio equipment. Assuming it’s a problem. In the audio devices, you should favour ‘balanced’ audio connection schemes.
The noise from the Pi is inherent in your design with or without an expensive fancy ‘audio’ power supply. The 5V/5A/25VA stock Pi5 power supply recommended by the manufacturers is perfectly adequate and well constructed enough to do the job.
A decent but cheap mass produced switched mode supply will be functionally equivalent to any linear supply of the same output spec, and it will probably have better short protection, under and over voltage protection etc. The rest is marketing, an electron is an electron…
With a Pi4, you can normally get away with a 3A stock supply, but you do need to have the capability to push the Voltage up to about 5.3/5.5V as the Pi4 is a bit fussy about voltage and doesn’t like droop.
Hello
got the tip to try IFI Power Elite, power part, which should be really good,
but has anyone tried this for Raspberry ?
I use the iFi PowerX, which supplies 5 V, 3.0 A, with A Raspberry Pi 4 and official 7" touch screen. When playing it’s fine, but when the tracks change, and presumably the CPU is under more load, I get the underpowered symbol showing up. The music still plays through my USB DAC though, so I’m not convinced it’s too much of a problem. I’ve not yet done a proper comparison with a cheap power supply, but so far I’m happy with the sound.