[sdiy] Microphonic PCB

[karl dalen]

Wierd! 
Gain should be fairly high to amplify ceramics.
When you say current caps what do you exactly
mean by that? The function?

regards
KD



> Hi all,
> 
> I'm scratching my head and wondering if anyone has some
> insight to help.
> 
> I have a prototype made up using mainly standard SMD parts
> (the main components used are: 0805 resistors, 0805 &
> 1206 ceramic multilayer caps, MLL34 silicon diodes and some
> dual shottkys, and SOIC TL074s)
> 
> I am able to tap the PCB and hear it!
> (obviously not very good)
> 
> Recently I was informed by Mr.G.Richter that SMD ceramic
> caps tend to be microphonic - you won't tend to notice it
> unless there is some amplification going on.
> Well, as the first stage of the PCB offers amplification I
> figured I should swap out the current caps and solder in
> some poly-box ones (no, it doesn't look all that neat!)
> The microphonics still remain..
> 
> Are other parts microphonic?
> 
> Cheers for any insight!
> Tom
> 
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