I have an amp in my car that powers a subwoofer and every so often I will get some sort of static. I was wondering if it's possible that I just don't have the wires connected very well. All the connectors on the amp, besides the line in, are screw terminals. What's the best way to prep a wire, either big (like the 8 ga. power and ground) or small (REM wire) to ensure a good solid connection?

 

Soldering ring and spade terminals is always beneficial but checking your ground is likely your best bet. It is doubtful you would get static at the speaker terminals unless you have excess corrosion.

If the static persists and it appears as though temperature or humidity are a contributor, then it could be something internal within the amplifier that needs to be addressed.

 

This has been an ongoing problem since about 3-6 months after owning the amp. It's a cheapy Dual, I think I might have paid $50 at most for it. But it still shouldn't be doing this. It's mostly only noticeable in between songs of if the audio is off. I know it isn't an input, because I can remove those and it will still make the static noise. It would be nice if the terminals were a different style for a more guaranteed connection. Whenever it finally goes out, I'll probably get a Polk 5 channel. Then I can power all the speakers. I think the stock are pretty capable if they're given the power. Some songs I had playing at max, vol. 40 on the '15 EX, weren't overly loud at that point while driving around 60 MPH.

 

It's probably not a poor connection but rather electrical or RF interference from something. To make it cheap, they had to cut corners somewhere, and noise resistance/filtering is one area to do that.

Is it better if you leave your cell phone at home? GSM phones frequently cause interference in poorly shielded systems (as the GSM protocol involves rather rapid switching of the RF amplifier on and off, not because of any faults of the phones).

If it is a connection, wiggling it while the amp is on will cause noise.

 

I'll test wiggling the wire while it's on. For a cell phone, is Verizon on a GSM Band? I thought they might be on CDMA, although I don't know if that matters. I don't know a whole lot about radio signals. I'll have to try that too. I used to wonder if maybe the RCA wires in my last car, that came with the install kit, were a little thin depsite running them on the opposite side of the car as the amps power wire. What your saying makes sense though, concerning the internal component integrity and RF shielding. I did read somewhere that a high level input doesn't suffer the same interference as low level because the voltage is great enough to overcome most "normal" interference.

 

I gave the ground a bare metal spot to connect to the car at, using the cargo anchor and bolt. I was still getting the interference, whatever it's coming from. My guess is there's something inside the amplifier that's gone goofy. I wouldn't know what to look for if I opened it up.

 

I'm still getting the crackling from the amp, I'm seeing how it works not in bridged mode. I didn't notice any noise on my drive home today, so I'll try it for a few more days to see how it goes. Since the amp is only sending one channel to the sub, can I combine both + and - leads to the high level input to get both sets of audio? Is that essentially what the amp does for bridge mode? I guess the difference would be that the signal going into the amp would be twice what's "normal" so I would have to dial down the gain.

I did open the amp last week and straightened out some of the capacitors and transistors that were bent over. There has definitely been a change in the type of noise produced. It used to make noise that sounded like someone scratching a microphone. Now the noise is much deeper in pitch, and more of a pop than static. I'm not sure what all this means, except that the components must be easily susceptible to interference as previously mentioned.

 

Don't connect different speaker connections from the head unit together. Anytime the audio signal is different between them (i.e. when you have actual stereophonic sound), the two outputs will be fighting each other and the amplifiers basically shorted out. You wouldn't get any additional volume that way, but you would get distortion and possibly damage or (hopefully) safety shutdown of the head unit.

As a general rule of thumb, two different outputs of any sort shouldn't be tied directly together. It's usually okay to split one output to two or more inputs.

Bridging of a stereo amplifier is a somewhat different matter. Each channel (which is, of course, a separate amplifier circuit) has one side of the output that is driven positive or negative, and the other side that's the circuit "ground"—this ground probably is the chassis ground of the car, but it doesn't necessarily need to be. In bridged mode, the two amplifiers are fed from a single signal and an inverted copy of the signal (the inversion being done internally), and the output is taken from the two driven outputs, with the neutral/ground outputs not connected. This gives you twice the power output—instead of, say, +1V and 0V on a channel you get +1V and -1V between the two channels. Each amplifier "sees" only half of the load impedance, however, so you are more limited in what speaker impedance you can hook up.

Popping noises suggest the possibility of bad (cracked or cold) solder joints in the amplifier. Very careful visual examination of these joints for larger components, like connectors and the power transistors and the electrolytic capacitors, may show the problems. They can be hard to see sometimes. It could also just be junky electrical/RF filtering in the amplifier, too.