Two channel18 watt PI input capacitor interaction.

RockinRocket · Post by **RockinRocket** » Sat Feb 07, 2015 4:46 pm

In a two input 18 watt long tail PI do the capacitor values choices effect the opposite channels frequency? Or any other interaction? And any reason not to use a .0047 as PI input cap? I could just try this but im sure a placebo affect might come in play and would like some knowledge going in. Thanks

JMFahey · Post by **JMFahey** » Sat Feb 07, 2015 8:34 pm

Wouldn't worry about "interaction" , specially because the PI there is also acting as a mixing/summing stage so both channels WILL mix and interact in those plates

Personally I like cutting deepest bass for cleaner sound, even while distorting.

Some Fender amps used as low as 500pF or 1000pF as PI input caps, go figure.

RockinRocket · Post by **RockinRocket** » Sun Feb 08, 2015 12:02 am

By "interaction" I was worried that signal from one PI cap would make its way to the cap of the other side thus losing what frequency to ground. No, it sounds like based on your reply?

Stevem · Post by **Stevem** » Sun Feb 08, 2015 1:15 pm

If you are switching one channel totally off then you are ok!

jjman · Post by **jjman** » Sun Feb 08, 2015 6:03 pm

The channels are out of phase in the PI so that interaction, if running both, is important.

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Two channel18 watt PI input capacitor interaction.

Two channel18 watt PI input capacitor interaction.

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Re: Two channel18 watt PI input capacitor interaction.

Re: Two channel18 watt PI input capacitor interaction.