auricap_capacitors Auricap Capacitors for more than Just Radios

Audience Auricap and Auricap XO Installation Instructions



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.)


Note: 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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WebPage last updated May 2022.