Hi everyone, before anything else, I would like to thank you for your patience with me.
I would like to build a basic audio project. The idea is that the finished product should sit firmly on my office desktop, have 2 ~20W coaxial speakers as a primary output. To drive that I'm planning to use 20W class-D Adafruit amp . There will be several audio inputs, two line-ins, arduino-controled FM radio, and a bluetooth receiver. Beside the speaker amplifier, I thought it would be nice for it to also have a CMoy headphone amp.
So far I wasn't able to figure out how to choose the right power supply. It's gonna be 12V @*~4A, with some step-down regulators where needed. From what I read so far, I should not even think of using switching power supply, but I've never held soldering iron in my hand so I don't really feel like building my own linear PSU. So SMPS it is, as it is a first project it does not need to be perfect on the first try anyway.
The thing is how do I choose the power supply? From what I read, the supply needs to be regulated (most of them are, ) and more importantly isolated. This is where I get really confused. What do I really need to look for? Should I look for class II supply, or is class I sufficient, or are these markings irrelevant to me? I was looking at MEAN WELL GS60A12, which is a class I supply, and MEAN WELL GST36B12, a class II adaptor. Then I saw a supply designed for hi-fi appliacations, SMPS-86, which uses MEAN WELL IRM-45-XX modules.
So, my question, what do I choose? Am I on a completely wrong track? Can I use the adaptors above without getting (too much) noise, and which one? Or should I use the class II module, and if so, can it be used as it is? Or is it necessary to build/buy a more sophisticated circuit? Or should I stop worrying because from I described above, it won't really matter anyway?
Thanks very much...
I would like to build a basic audio project. The idea is that the finished product should sit firmly on my office desktop, have 2 ~20W coaxial speakers as a primary output. To drive that I'm planning to use 20W class-D Adafruit amp . There will be several audio inputs, two line-ins, arduino-controled FM radio, and a bluetooth receiver. Beside the speaker amplifier, I thought it would be nice for it to also have a CMoy headphone amp.
So far I wasn't able to figure out how to choose the right power supply. It's gonna be 12V @*~4A, with some step-down regulators where needed. From what I read so far, I should not even think of using switching power supply, but I've never held soldering iron in my hand so I don't really feel like building my own linear PSU. So SMPS it is, as it is a first project it does not need to be perfect on the first try anyway.
The thing is how do I choose the power supply? From what I read, the supply needs to be regulated (most of them are, ) and more importantly isolated. This is where I get really confused. What do I really need to look for? Should I look for class II supply, or is class I sufficient, or are these markings irrelevant to me? I was looking at MEAN WELL GS60A12, which is a class I supply, and MEAN WELL GST36B12, a class II adaptor. Then I saw a supply designed for hi-fi appliacations, SMPS-86, which uses MEAN WELL IRM-45-XX modules.
So, my question, what do I choose? Am I on a completely wrong track? Can I use the adaptors above without getting (too much) noise, and which one? Or should I use the class II module, and if so, can it be used as it is? Or is it necessary to build/buy a more sophisticated circuit? Or should I stop worrying because from I described above, it won't really matter anyway?
Thanks very much...
Hi. I think you are possibly worrying unnecessarily about using SMPS with your amp. Although I haven't used one myself yet, I have looked into using one for a JLH class A amplifier I am considering building. People have used them successfully with JLH and Pass Labs amplifiers, both of which are more susceptible to power supply noise than class AB or class D amplifiers.
I checked ripple+noise level on the first and second supplies and both show 100mV which looks like a very low value to me.
I can´t imagine how that could be heard through the speakers,given that any competent amplifer design will have good supply noise rejection.
To boot, you chose a Class D amplifier which by itself has *some* HF hash at its output, yet that is not annoyig or even perceived, so .... don´t overthink it.
FWIW I commercially make 12V battery powered portable amplifiers, for street musicians, and for quick bench tests use a plain PC power supply , which was NOT designed for Audio use ... never a problem
I can´t imagine how that could be heard through the speakers,given that any competent amplifer design will have good supply noise rejection.
To boot, you chose a Class D amplifier which by itself has *some* HF hash at its output, yet that is not annoyig or even perceived, so .... don´t overthink it.
FWIW I commercially make 12V battery powered portable amplifiers, for street musicians, and for quick bench tests use a plain PC power supply , which was NOT designed for Audio use ... never a problem
@JMFahey , I was thinking of making a separate PS for my 20V MOFO power amp (monoblocks -> single case), using a PC power supply along with a DC-DC step-up and CRC filter. I see ASUS power supplies for ~fifty usd, and the 12V rating is 450W. Way more than both channels will draw, IIRC.
Have you investigated the noise levels of the PC power?
Kind regards,
Drew