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HELP: I am building an Pixie 2

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sm5mek:
And i have a strange motorboat sound from the receiver,  LF is LM386, anyone having tips to filtering this?  :-\

PG4I:
Hi Jenny,

make sure your power supply decoupling is okay. Where the supply is connected to the LM386 add a 100uF electrolytic capacitor in parallel with 100nF ceramic. Connect them as close to the LM386 as possible. Also, make sure your grounding leads are as short as possible.

WH7TT:
Trying using a battery as well to see if the sound is still there. That will tell you if it is the Power Supply or something else.
Edward
WH7TT

sm5mek:

--- Quote from: WH7TT on April 01, 2015, 17:17:06 UTC ---Trying using a battery as well to see if the sound is still there. That will tell you if it is the Power Supply or something else.
Edward
WH7TT

--- End quote ---
Well i shifted the battery and the putt putt was dissapearing. NICE. Before that i also found a tiny tiny shortcut :-) but the motorboat was still rhere, could be that the shortcut was taking so much current so the IC didnt get enough current. Now weak hissing like a lazy cat. More tests in future.

n7eku:
Hi Jenny,

My first post here :-)

Almost every design I see using the lm386 forgets that pin 7 should be bypassed to ground.  Any small value electrolytic should be fine (5-20uF) and helps a lot.

Have fun with your pixie!

73,


Mark/n7eku

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