But why would wire benefit from a  polarizing voltage? Yes, there is a capacitance associated with any interconnect, but that capacitance is minor in audio terms and it does need to "form."
  One thought is that polarizing voltage allows the wire to work in a single-ended fashion. Maybe the molecules within the wire resent a reverse in voltage potential, a hysteresis effect of sorts much like that of the permeable metal in the core of an output transformer, which tends to sticks to one polarity and then the other. By placing a polarizing voltage between wires, makes the audio signal ride on top of the 9 volt potential. For example, a 2 volts input signal will appear on the hot lead as a sine wave cresting up to 11 volts and bottoming down to 7 volts, but never swinging negative relative to the ground lead.
   The analogy that comes to mind is that of a Class A amplifier vs. a Class B amplifier. Without the polarizing voltage, the interconnect leads are like the output devices of a Class B amplifier in that in the absence of a signal they remain dormant, but with signal they become active. On the other hand, with the polarizing voltage, the interconnect leads are like the output devices of a Class A amplifier in that they remain constantly on.
   I admit that this is a stretch, but maybe something like this is going on in most tube audio circuits in that the high-voltage, single-polarity power supply that is the norm and single-ended topology of most of circuitry combine to unintentionally polarize most of the components and allow only unidirectional current flow through these devices. Maybe all wires should carry some idle current?
  How do we put these ideas to a test and without spending several hundred dollars? My thinking is that since the outputs of most tube line stages are capacitor coupled and many tube power amplifiers comprise an input coupling capacitor, it would take very little work to wire in a polarizing bias voltage for the interconnect. 

   Perhaps you have seen a variation on this theme: an add-on audio accessory that comes in two boxes and is said to improve radically the sound of your system. (When did you last read of an audio accessory that did not radically improve the sound of your system?) One box plugs into the power amplifier's input RCA jack; and the other, the preamp's. In between the boxes goes your preexisting interconnect. Inside the first box, there is only one coupling capacitor; within the other box, a 1M resistor, a 9 volt battery, and a coupling capacitor. The cost is on the order of six hundred dollars.
   At first glance this sounds like a good way to spend far too much money on something that is not really needed. Furthermore, why would someone want to add more passive components in the signal path? The secret premise behind this accessory's design is the idea that interconnect sounds better with a polarizing voltage developed across its leads. But, on the other hand, certain audiophiles, whose ears I trust, tell me that in fact this device does make a very noticeable improvement. What could be going on here? I have read where a manufacturer of short-wave radios found that by applying at least a small polarizing voltage on all the capacitors used in the unit brought about a very measurable increase in high frequency response (RF). Now, I am sure the capacitors used in the radios were the cheapest possible, which means Mylar and electrolytic. Maybe the electrolytic capacitors, which are very much removed from the ideal (a vacuum capacitor) and are very much a chemical stew of materials, need a constant polarizing voltage to "form" correctly.

pg. 13

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