Need some advice with secondhand speaker upgrades

I bought a used Microlab M600 2.1 system for R250 ($20). They're way better than what I had before, but the sub makes a low, electrical humming sound that's very noticeable to me. Even when there's no satellites plugged in, it makes that noise. They're still under warranty, so I sent them an email, but if I get a negative response, I'd wondering what my best options would be.

There's used Thornet & Vander Gut speakers for R500 ($38). They're bookshelf speakers, and I'm not sure if I'd need an amp to use them. These might be a good idea because I could build on the setup later, by adding a sub.

There's also a used Logitech X-530 5.1 system for R700 ($54) that's two years old.

That seems to be the best of the currently available used audio stuff in my area. If I can't get the sub for the Microlab system sorted out, should I go for the Thornet & Vander or the Logitech system, because the humming will drive me insane. Or should I just save up and buy something new? Max budget is around R1000 ($77).

I'm not interested in loudness. Just clarity, and obviously they must be silent at idle. None of this humming stuff my current setup does.

Before you go and replace the speakers, have you tried finding the source of the hum? Fixing a hum can sometimes be pretty easy.

http://www.psaudio.com/ps_how/how-to-find-and-fix-hum/

I don't know how accessible these sorts of things are, and I don't know what the general opinion of them is on the forum, but around here in america you can pick up a nice old set of Panasonic speakers for practically nothing.


This set is what I have. The speakers can extend on long wires, I keep the deck in front of me on my desk and run the speakers to either side. I have analog control over basically everything and the sound is really nice imo. All it really requires is a 3.5mm to RCA cable.

On the humming issue, I don't find that these hum at idle at all. Of course if you idle them with the volume all the way up it's gonna get a little staticky, but software volume controls should be raised before you raise them on a set anyway.

Purely theoretically speaking, this is a sign of electrolyte capacitors drying out.
Electrolyte capacitors use liquid, known as electrolyte, therefore the name. With time the liquid is drying out and the capacitive value of the capacitor is changing. So the element is going out of the specifications and the noise accures.
Other possibility is the transistors themselves. When the transistor is used in amplifying mode, there needs to be constant voltage applied to it. The power, supplied by the power supply is never perfectly even, and some times the transistors take the changes in the power as a signal and amplify it. Since they are really small changes it's a really weak noise.
Now combine the power imperfections with the dry capacitor and voila... Static noise...
That is pure theory though.
It can be trillions of other things...

If there is an amp built in to the sub (I'm guessing that there is), check the cables to it and the shielding inside it. If you're super duper cheap, pop open the sub, and glue layers of flattened aluminum foil to the inside walls. No guarantees, but that is one way to create effective shielding for practically no cost.