lm380 2watt amp

prorms · 17th August 2006, 12:48 AM

have trouble at the point were the treble bass section meets
the lm380 singal does come out be its very low

Leolabs · 17th August 2006, 01:59 AM

Why no output coupling cap???

singa · 17th August 2006, 02:06 AM

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.

anatech · 17th August 2006, 02:58 AM

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.

Quote:

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

17th August 2006, 02:06 AM	#3
singa diyAudio Member Join Date: Apr 2004 Location: near	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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17th August 2006, 01:59 AM	#2
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	Why no output coupling cap???

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