Zoom 15watt Modeling Amp BUZZES

[Megabunny]

My 15Watt ZOOM SS Amp makes this god awful Buzzing http://www.youtube.com/watch?v=a90r9CmQ8Eg

no matter what i do it wont make ANY other noise. not louder not quieter. guitar input make no difference either.

any ideas?

TY guys

[joecool85]

Sounds like when I had a SansAmp with a blown TDA2050 power amp chip.  It also had two burned out rectification diodes.  I'd say open her up, odds are you have some burn marks on your pcb.  Even if you don't we can help you sort out what's going on.

[mensur]

It's blown amp, you have to replace the whole power section.That buzz you hear is DC voltage, and it can fry your speakers.

[joecool85]

It's blown amp, you have to replace the whole power section.That buzz you hear is DC voltage, and it can fry your speakers.

You say "whole power section", but that should just be a single chip since most cheap amps use an IC for their power amp section.  Should be a TDA2030, LM1875 or similar.

[mensur]

It's blown amp, you have to replace the whole power section.That buzz you hear is DC voltage, and it can fry your speakers.

You say "whole power section", but that should just be a single chip since most cheap amps use an IC for their power amp section.  Should be a TDA2030, LM1875 or similar.

I know it's a chip amp, but maybe there are faulty caps, resistors, again it's only few components.

[joecool85]

I know it's a chip amp, but maybe there are faulty caps, resistors, again it's only few components.

Yes, it is possible in theory that there couple a bad cap or resistor somewhere as well.  I've not seen it happen though.  It seems the IC always goes well before taking out any of the discrete components.

[Megabunny]

is this the chip your talking about?


"http://a6.sphotos.ak.fbcdn.net/hphotos-ak-snc6/224254_10150174223567043_722767042_7004812_7465298_n.jpg"

[teemuk]

^ Yes.

Definitely sounds like blown output chip. Don't keep the faulty amp on like that too long, it'll toast the speaker in no time. Then the $1 repair turns to a ~ $50 - $80 repair.

Repair of this stuff is indeed often as easy as throwing in a replacement chip. I'd still momentarily unplug the speaker and (after the repair) measure that no DC voltage potential exists in between the speaker leads just to be on the safe side.

[joecool85]

Yeah, that's the one.  Replace that baby and away you go!  (Probably).  Every now and then it might take something else with it, but it's unlikely.  Just buy two of whatever that IC is, they should be cheap anyway.  That way if you blow the first one you can figure out why then install the second one.

[DartPlayer170]

It's also a good idea to buy some heat sink compound and re-apply to the new IC. Clean the old guck off the heat sink first. This will help prevent the new IC from burning out quickly.

[Megabunny]

Kk here's the update.

Ordered 5 x TDA2030a
Took the old one ff to double chck part numbers and the thermal paste still has the foil on the inside, so its wasn't properly applied when it was made.

Gonna fit new TDA2030a then post update.

Thanks guys... much love.


Mike.

[joecool85]

Kk here's the update.

Ordered 5 x TDA2030a
Took the old one ff to double chck part numbers and the thermal paste still has the foil on the inside, so its wasn't properly applied when it was made.

Gonna fit new TDA2030a then post update.

Thanks guys... much love.


Mike.

What do you mean "still has the foil on the inside"?

[Megabunny]

The chip comes pre packed with a little bit of thermal paste. You peel off the foil and stick it to the heat sink,

cheap computer processors usually come with it.

So I peeled it off and the thermal paste was still fresh. The guy who built it in the factory must have forgotten to take it off before screwing it together.

The TDA2030a chip is visibly burnt so I'm still going to replace it. Then I'll Update you guys, parts are coming from Hong Kong so it may be as much as 20 days before I reply again. Unless you guys have any question's.

[joecool85]

The chip comes pre packed with a little bit of thermal paste. You peel off the foil and stick it to the heat sink,

cheap computer processors usually come with it.

So I peeled it off and the thermal paste was still fresh. The guy who built it in the factory must have forgotten to take it off before screwing it together.

The TDA2030a chip is visibly burnt so I'm still going to replace it. Then I'll Update you guys, parts are coming from Hong Kong so it may be as much as 20 days before I reply again. Unless you guys have any question's.

Weird, I've not ever seen that.  Sounds like that might be why you had problems.

[teemuk]

Are you sure it was the foil and not the electric insulator that you need between the chip and the heatsink?

Whenever I have bought those chips from a local "radioshack" wannabe store they have always lacked a peelable foil and pre-applied thermal paste.