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Old 17th August 2006, 12:48 AM   #1
prorms is offline prorms  United States
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Default lm380 2watt amp

have trouble at the point were the treble bass section meets
the lm380 singal does come out be its very low
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Old 17th August 2006, 01:59 AM   #2
Leolabs is offline Leolabs  Malaysia
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Why no output coupling cap???
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Old 17th August 2006, 02:06 AM   #3
singa is offline singa  Singapore
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Smile lm380 2watt amp

Just a guess.There seem to be missing junctions/black dots or connectors.See R6,11,12 and 8. C1 and also negative input of opa134.Output to lm380? Good luck.
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Old 17th August 2006, 02:58 AM   #4
anatech is offline anatech  Canada
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Hi seanmacss,
Tell me that your +10V is not connected to the inverting input of the op amp driving the LM380. The output also has an AC short to the positive supply through C1 (goes to ground and +10V, right?).

I haven't seen a tone control with C6 and C8 in those positions, try removing them.
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Why no output coupling cap???
Absolutely! Not unless you need to bias that input to 1/2 Vcc from an external source, then what you are doing is fine.

-Chris
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