I have this little radio board but when power is applied it makes scratches and pops for half a second before it gets quiet. I wonder if there is proven way of muting input of the amplifier and slowly fading it in by, I dunno, using a transistor and a capacitor with some resistor to slowly close it, when in open state on power up it would ground the input maybe?
As usual, schematic, please.
Paul
There are a lot of ways of doing this. Does the little radio board have several outputs, is it working, what is it. Link to technical information please. We have the same problem with the amplifier, there are thousands available from a small ic to a megawatt system. Links to technical information on this will also help. And as Paul_KD7HB asked post your schematic with technical links to the parts as well. You might also research squelch circuits.
Hello
Sometimes a good HF ampilfier will help. Connect an arial to your little radio board.
Only when you provide actual information - Web links, circuit diagram - will we know what the problem is. 
Otherwise, - "XY Problem". 
It is LCD FM RX VER2.0 lcd fm rx ver2.0 - Google Search
I think I might solve it with the amplifier board. I have ordered 2 different boards, both have mute pin, but one has fade in pin as well, so it could be easier than looks.
Let us know for sure if you have resolved the problem. Good job, you kept on looking!
So I got my PAM8610 board, it has fade in control hardwired to always on and while it solved the problem of radio module making noise on start up, the PAM board itself makes some cracking noise on start up. I’m getting the same board from another supplier, will see if the board is faulty, otherwise there is one more chance with TPA3116 board, I have good feeling about that as I used them before, so hopefully will have quiet start.
Good Luck and thanks for the update.
So, I had to abandon the idea of using class D amplifier all together. They create too much RF interference and I needed it for FM radio project. Even though I managed get rid of annoying crackle by using different chip, it was only letting me to tune to 3 out of 26 stations. In the end I found TDA1015A old stock that is low voltage and could work between 6-8.4V
You could add a squelch switch
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