Stable and "Clean" Power Supply for a 5v Amplifier

[spaceman5]

Hi


I need to buy a Power Supply that will supply 5v DC for an Audio Amplifier.

What can I use that will give a stable and clean 5v?

Is there a chance that a Switching power supply can do a good job here?
(usually the 5v USB Power Supplies have some ripple.. but maybe via adding a capacitor or a small circuit to help straighten the wave?)


Thank you

 

[Mooly]

5 volts at how much current ? An SMPS could do a very job and should not need additional smoothing.

https://cpc.farnell.com/ideal-power/15dys605-050120w-5/ac-dc-power-supply-5v-1-2a-vi/dp/PW04130

Or you could build a traditional linear supply using a transformer/bridge/caps etc.

 

[spaceman5]

5 volts at how much current?

I will mostlikely be OK with 1A..

An SMPS could do a very job and should not need additional smoothing.

Really?
How is this happening?
The Amplifier does some smoothing?

If you look at the output of a 5v Switching power supply with a scope,
you will always see some ripple..

In some AC Adapters there is more, in some less, but a ripple will be..

The amplifier knows how to handle this?

 

[Mooly]

The high frequency ripple should be very small from any decent switching supply. If you clip your scope ground lead to the probe tip (so shorting the scope input) and then bring that near an SMPS you will probably see noise (which is radiated) but that is not the same as ripple.

Actual ripple should be a few 10's of millivolts at most.

 

[spaceman5]

Actual ripple should be a few 10's of millivolts at most.

Interesting..

So a few tens of Mv does nto affect amplifiers?
Even Class D amplifiers?

Quite surprising..

 

[Mooly]

A lot depends on the amplifier itself. A Class D amp that that takes a normal analogue signal will be a type that uses overall feedback (known as 'closed loop') type and these are less susceptible to supply noise than 'open loop' types.

If you feel its a concern then you need to research the type of amplifier you are actually looking at and see whether it is affected and by much.

 

[spaceman5]

Thank you very much Mooly..

 

[spaceman5]

If I take apart some 2.0 amplified speakers, and they have inside an AC Adapter based on a big transformer,
Is it possible to say, generally, that we can replace the Transformer based AC Adapter inside, with a Switching AC Adapter?

I ask this because in many amplified speakers, the AC Adapter inside is Transformer based, and not the lightweight switching ones..

 

[Mooly]

Providing you can derive the correct voltage/s from the SMPS then it should be fine. Remember many amplifiers with conventional transformers generate 'split' or dual rails of equal positive and negative voltage.

 

[spaceman5]

Remember many amplifiers with conventional transformers generate 'split' or dual rails of equal positive and negative voltage.

Oh..
But a Switching power supply will not provide that..

 

[Mooly]

Yes, an SMPS can do that easily but the problem is that they are not very common. You would need to know the voltages required as a starting point. You can also use two SMPS to derive dual supplies as long as they are of a suitable type.

 

[spaceman5]

Thank you Mooly 🙂