[R-390] C553

[Charles Steinmetz]

David wrote:

>For C553, TC, VC, DF, DA, even IR and piezoelectricity, are 
>irrelevant if held to real-world limits.

Not so.  I was easily able to see additional IMD on the spectrum 
analyzer when I replaced C553 with a Class II ceramic (e.g., Z5U or 
X7R).  A Class I ceramic (C0G/NP0) should solve that 
problem.  Film-and-foil caps also do not generate measurably 
increased distortion.  So, if one decides to use a ceramic for C553, 
one is well advised to use a C0G/NP0 type.  They're harder to find, 
but they're out there (e.g., AVX SV01AA103JAA).

Best regards,

Charles