Auricap Capacitors for more than Just RadiosAudience Auricap and Auricap XO Installation Instructions
AURICAP APPLICATION / INSTALLATION NOTES
Auricap film capacitors are not polarized. However, Auricaps have an outside foil
that is a very useful noise shield when input and output impedances are considerably
different values and it is connected to the lower impedance.
1) In all coupling applications the input to the Auricap should be the black lead and
connected to the signal source or circuit output with the red lead continuing on to the
next circuit input.
2) In all power supply decoupling applications the outside foil or black lead should
be connected to ground and the red lead connected to the voltage to be decoupled.
This is true for decoupling either voltage polarities.
3) In loudspeaker crossover applications, if the Auricap is in series, like feeding a
tweeter, the black lead connects to the input binding post and the red lead connects to
the tweeter. Where the Auricap is in parallel, as typically used for woofers, the black
lead connects to the speaker connection that connects to the input binding post and the
red lead connects to the other speaker terminal. Follow these same rules for midrange
connections where you will have a combination of both.
The idea is to always have the outside foil connected to the lower impedance to
provide outside foil shielding to noise. Circuit outputs are always lower impedance
than inputs and should be connected to the outside foil.
Auricap-R (R version) caps
have one lead longer than the other. The long lead is the
inside foil and to be treated the same as the red lead on the standard axial Auricaps.
It follows that the shorter lead is the outside foil and functionally the same as the black lead.
Do not use bypass capacitors in the signal path. A single capacitor for DC
blocking/AC coupling creates a simple path with one time constant. The signal quality
will be compromised if a bypass or multiple bypass capacitors are added to a signal
path capacitor. Bypass capacitors were used in the past to bypass low quality film
capacitors or electrolytic capacitors. The bypass was the lesser of two evils. With the
advent of better quality film capacitors the need for a bypass capacitor was eliminated.
Bypass capacitors create multiple signal paths with multiple time constants. These
time constants are very short but they can still be heard as a smear or overall loss of
Always bypass power supply capacitors. This maintains a low source impedance to
the power supply over a wide bandwidth. If budget and space permit it is good to use
multiple value power supply bypass capacitors with the smallest value being installed
directly at the active device. (Tube or transistor.)
Some Auricap XO capacitors have two
red leads (rather than a black and red). In this
case one of the red leads will have a black mark on it. This red lead “with the black mark”
should be treated same as the Auricap black lead (outside foil) for installation purposes.
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