Re: Recommended capacitors for AF circuits

On Fri, 21 Apr 2006 20:53:11 GMT, Rich Grise <richgrise@xxxxxxxxxxx>
wrote:

On Thu, 20 Apr 2006 02:57:39 +0000, Ben Bradley wrote:
On 19 Apr 2006 12:31:41 -0700, Winfield Hill
<Winfield_member@xxxxxxxxxxx> wrote:

As I cautioned Thomas, the common popular ceramic capacitors,
which are fine for bypass, etc, are bad news in audio filtering
circuits. This shows with 0.07% distortion values. Moreover,
the distortion output of the 6200B that shows what's left after
subtracting the fundamental, reveals the distortion products
contain a number of evil-looking strange harmonics, which no
doubt are as evil-sounding as they look.

Although the 0.07% ceramic capacitor distortion is only a few
times higher than a LM1036 makes at low signal levels, it's
present at all signal levels, and I'll wager it sounds worse.

This doesn't even go into another serious problem with ceramic
capacitors in audio circuits (and in MOST OTHER circuits where there
might be the slightest bit of mechanical vibration) is that they are
MICROPHONIC. Grab one at random, connect it to the input of an
amplifier, and hit it with a pencil to hear thumps come out of the
speaker. Or connect it to a DSO, and see the largest peak voltage you
can get out of it before it breaks.

Not to mention PIEZOELECTRIC. ;-)

Well, yeah, that too. :-)


Cheers!
Rich

.

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