Speaker Humming/Crackling

[Ian]

I've had a problem with my speaker system for quite a while now, but its not becoming too much of a problem.

I have the ABit SP60 speakers, and after getting back from uni they sounded great (I hadn't used them in months). After about 2 hours they started to lightly hum, and now a day later its loud humming and crackling... it does this until I leave them for a few days!? What on earth could be up? I doubt it is the satellite speakers as they work in other things, but the problem is coming from the Amp/Sub unit.

 

[Quadophile]

?!?!?!

Why did the amplifier hum?

Answer: Because it did not know the words!

That was just to cheer you up!

As for humming, my experience says it could be the transformer in the sub unit which is faulty. If so, I am afraid you will need to replace it.

I am afraid there is very little I can do on the forum to rectify the problem since it needs to be physically checked.

I am hoping all the connections are done in the right way? At times the simple problem is because the wiring is not done right.

Let me know if it is so and you problem is hopfully due to this only.

 

[Ian]

lol - that joke got me

Its all wired up correctly (unfortunatly!), so it can't be that... Is it probable that it is the transformer causing that? I might open it up and see whats inside

 

[Quadophile]

I cannot think of any other reason for the humming sound. If you open it up the first thing you should check is if the transformer is securely bolted down, a loose screw can also get the transformer to hum at times.

I was curious to find out what was inside your sub unit so did a bit of Google search and found an article which gives a good view of the inside.

The innards of the sub unit!

 

[Ian]

Thanks Quad

I'll take a look now Lets just hope there are no nastly large capacitors in there

 

[Ian]

Ummmmmmmm... I took it apart... nothing was out of place, but tightend the screws.... no luck

 

[Quadophile]

Sorry to hear that

Can you contact the outlet and get the folks to let you know what could be the possibaly wrong?

How about contacting Abit themselves and getting some feedback?

I am just keeping my fingers crossed!

 

[Ian]

I'll send Abit an E-Mail and see whats up

Thanks again for your expert advice and help Quad

 

[Quadophile]

Sorry about that

I do not want to do any guesswork and come up with a dozen new things as that is not the right thing to do.

I keep my fingers crossed, your best bet could be the suppliers themselves. They sure have a vast database of feedback and they may just have a clue as what could be wrong.

 

[1nteger]

Ian
By the time you read this you may have already sorted out your humming speakers problem. Just thought I'd mention that I had an identical problem with a pc a couple of years ago. Eventually. I ended up opening the machine and cleaning it...I used a compressed air cannister around everything. However, I also re-installed windows. After I put the machine back together the humm and crackle had gone completely...and I still haven't got a clue what it was that caused it. While my system was pretty dusty inside, I vaguely remember testing it after cleaning and the humming was still there, so I conviced myself that it was the OS re-install that sorted it...but who knows?

Another thought: are the speakers positioned near a wall that has either...electrical power lines running through or some electrical thingy on the opposite side in the next room?

You can tell by the nature of these suggestions that I don't know much about sound systems and stuff! But hey, if the techy stuff fails, it never hurts to get a duster out

 

[Eric Portelance]

1nteger is right...if the speakers are cheap and not very well insolated, they could be receiving interferance from their surroundings. One example of this is cheap speakers will interfere with monitors if they're placed too close and vice-versa.

 

[1nteger]

Originally posted by Eric Portelance
1nteger is right...if the speakers are cheap and not very well insolated, they could be receiving interferance from their surroundings.

8) I shall add 'Sound Engineer' to my CV asap, along with:
Brain Surgeon (I gave paracetamol to someone once and it cured their headache) and I'm also a fully qualified Psychiatrist, as I once diagnosed someone as a 'Mad Bastard' for buying an £800 PC from Dell and paying £2,500 for it.

 

[Ian]

These are pretty well shielded speakers I'm afraid - and I've tried them in a totally different location on a TV

 

[Eric Portelance]

Is it possible your plugs on the back are a bit dirty or something? Or they could be loose. It could be so many things. Speakers are really tough to diagnose.

Oh, and 1nteger...try norgesic for serious migranes (if you can get a prescription). It's also a muscle relaxant so you feel really de-stressed. It's great.

 

[Ian]

Had another go with the speakers today, it seems if I leave them grounded for a few days they work fine for a bit?! Doesn't make much sense....

Cleaned the contacts too as suggested, but to no avail - although they are nice and shiny now

 

[1nteger]

Ian...since you mentioned that they are ok if grounded for a few days, ithe following may be of some guidance. There's a possibility it's the wire to the speaker or sub-woofer rather than speakers itself. The first link is a general set of things to try to rid your system of speaker humming, but there's another link on that page (in point 5) that goes into more detail...may be worth checking out

http://www.techtv.com/screensavers/answerstips/story/0,24330,2597742,00.html


...another thing that may sound a bit daft..have you tried re-installing your sound card drivers?


...and a final troubleshooting question: it didn't start to happen when Hmmm joined the forum did it? (I know, I know)

 

[IanH]

Ian,
This is quite a common fault with any equipment that has an internal PSU (Power Supply Unit). With most PSU's, you have a transformer, a fuse/fuseholder, either a half or full wave bridge rectifier and 2, 3 or 4 electrolytic capacitors. (vertical blue tubes)

The electrolytics smooth out the electrical signal and the rectifier along with a few other components convert the raw ac out of the transformer in to dc.

If an electrolytic breaks down, it becomes as whats known as "Live" or "Gone to earth". That is what is causing the hum, because when you first switch on, there is no hum, this is because the capacitors havent "Warmed" up, but give them a chance and they will hum for you, if they dont get any attention, they will almost certainly smoke and hum.

The best thing you can do Ian, is to take them to a local computer club, hoping there's a guy there whois an "dabber" with a test meter and iron, or radio & tv repair shop. But if it gets to expensive, then ditch em and buy another set.


Ladies and Gentlemen put your hands together for the one and only, Abit Smoke and Hum Duo.

PS If they are Abit speakers, they must be humming Sanyo's theme tune......... Think about it Abit and Sanyo, need I say more.

 

[Ian]

Thanks Ian

I'll give this a try at the weekend once I get back to Manchester, as that is where all my electronics equiptment is This sounds promising! I'll let you know how it goes :spin:

 

[1nteger]

Originally posted by IanH
...With most PSU's, you have a transformer, a fuse/fuseholder, either a half or full wave bridge rectifier and 2, 3 or 4 electrolytic capacitors. (vertical blue tubes). The electrolytics smooth out the electrical signal and the rectifier along with a few other components convert the raw ac out of the transformer in to dc. If an electrolytic breaks down, it becomes as whats known as "Live" or "Gone to earth". That is what is causing the hum...

...er...yeah...I was just going to say that myself, but I thought it was a bit too obvious...:roll:

 

[floppybootstomp]

Ian H, he offer good advice

One of the most common causes of hum present on audio systems is either in faulty audio connector leads (phono) or caused by large electrolytic capacitors.

As well as becoming faulty, a capacitor can also develop a dry solder joint. It's worth checking all connections to any large capacitors you see and re-soldering if necessary.

Might also be worth whipping out the main amplifier pcb and checking for dry joints on the underside, particularly on the larger semiconductors.

Good luck.