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Monday, February 22, 2010

Battery Biased Caps in Passive Crossover for High Efficiency speakers


"The battery is tied between two capacitors and a high value resistor therefore there is no direct current path for the battery to discharge. The capacitors block DC current and the high value resistor raises the AC impedance so attenuation doesn't occur through the battery. The battery will last for years. The only discharge path would be through the capacitors due to leakage current, which will be extremely small.

To install a battery biased network perform the following:
For each series capacitor (high pass) in the network, replace it with two capacitors of twice the value and series wire them together. ( i.e. replace a single 10uF cap with two series wired 20uf caps) Tie the + terminal of the 9V battery between the two capacitors. Next connect a 1 or 2 Meg resistor to the - terminal of the 9V battery. Lastly, connect the other end of the high value resistor to the return leg of the network.

To play it safe take your voltmeter and make sure there is no DC voltage on the feeds to your tweeter. If you do it right there should be no DC voltage. The caps block it from getting there. You should only see voltage at the node where the 2 caps and the resistors meet....

And yes, it will make a difference with high efficiency speakers. The battery biasing lifts the low level single away from the zero crossing point of the capacitor's dielectric, thus increasing detail that would be otherwise lost."

... from AA (thanks all...) and after brainstorming with Tim...

Duracell: the best audiophile friend? Would seem definitely "Yes!"

Nuff said...

1 comment:

Tubes for sound said...

Another input from AA :

"To play it safe take your voltmeter and make sure there is no DC voltage on the feeds to your tweeter. If you do it right there should be no DC voltage. The caps block it from getting there. You should only see voltage at the node where the 2 caps and the resistors meet...."

TG