Cheapie 2.1 Speaker Set with static in left speaker

May 29, 2007 8 Replies

While dumpster diving I found a 2.1 speaker set. Static in the left speaker.



I swapped speakers, problem persisted. I swapped the op amp out with a known good one, same thing.



I'm new to this kind of thing, so I'm a bit perplexed as what to try next. It's not the source, I've tried several different sources. Wiring appears to be okay. Sound to the subwoofer and the right speaker is okay.


http://www.pealefamily.net

I googled your problem and I got 40,020,203,029,209,102,683,204,603 hits and they all say that you get what you pay for. But if you want to buy a new speaker system just google your problem yourself and click on one of the 50,000,000 advertisments on the top.

Look at the mixer IC. It generally does tone control/balance/volume. Cost about $4 to replace. If there are any discrete transistors, and I doubt there are, try tapping them with something non-metallic and see if it affects the sound. Otherwise, throw it away, ain't worth your time.

Malissa Baldwin wrote in news: snipped-for-privacy@p47g2000hsd.googlegroups.com:

Well, "duh." But what fun is that?

http://www.pealefamily.net

"Dave" wrote in news:uVZ6i.63660$Xh3.6455@edtnps90:

It's a back-burner project, just something I've been tinkering around with in my spare time. I'll check the mixer IC tonight.

http://www.pealefamily.net

in which speaker?

Just short the audio out at the various points in the signal chain (dont short power amp output tho). When shorting before a stage made no difference & shorting after it killed crackling, you know where its coming from. Prodding with a bit of plastic also helps locate if its a dry joint.

NT

snipped-for-privacy@care2.com wrote in news: snipped-for-privacy@g4g2000hsf.googlegroups.com:

LOL...in the left speaker. If the problem traveled, I'd have found my problem. ;-)

I touched up every joint I could, esp. the connectors on the PCB.

What do you mean, short the points? Take a wire and jump the signal closer along in the chain to the output?

http://www.pealefamily.net

No, jump the signal to ground. You're effectively killing the audio signal input from that point on. If the crackling persists, that means it's being introduced downstream of the point you've shorted. Just keep moving downstream along the signal path until the crackling goes away. The component just upstream of your jumper point is the likely culprit.

That is the preferred way of pinning down a problem like this, and is often more effective than using a 'scope to try to distinguish between the crackly noise, and the inherent stage noise. I would, however, warn agains employing a direct shorting wire to do the job, unless you have schematics for an amp to know exactly the 'safe' points to apply a direct ground connection to. There are places that you certainly don't want to short directly to ground, if you want the components to keep their magic smoke locked in. I would recommend that you use a 47uF 35v capacitor, negative leg to ground, as your 'shorting wire'. The actual value isn't critical - whatever comes to hand.

Arfa

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