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[DPRG] RE: DPRGlist Digest, Vol 66, Issue 2

Subject: [DPRG] RE: DPRGlist Digest, Vol 66, Issue 2
From: David Jannke david at proboticsamerica.com
Date: Wed Nov 4 12:47:52 CST 2009

>So bottom line my question is this.  How can I filter the power going into
>the MM5450 and/or the speakers to ensure that both receive sufficient power
>but "feedback" doesn't get into the audio system and/or the speaker power
>isolated from the electronics?

This kind of thing used to be a constant problem for me.  The answer was
generally an RC filter via 'big honking capacitor' (10k+ uf) between pos and
ground on the offending unit's power supply.  Automotive audio filters also
work pretty well for that kind of thing.  

Adding a separate voltage regulator would probably work as well, I suspect
but don't know for sure that dedicating a regulator with an output voltage
of 9v or so to the MM5450 would work best as voltage variations would have
limited effect on the 5v regulator serving the vMusic.  

One other thing to check - can your batteries easily handle the amp loads of
both sound and lights?  If they can sort of handle them you get big
variations in the voltage when the current draw is high.  You might also get
a similar effect if the 5v can's source enough current for the vMusic, but
I'm speculating there.

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