Hissing Sound Through Speakers When Inverter is On...

**jroskos** · 01-13-2009, 05:23 PM

Hello Everyone,

I have a laptop in my work vehicle and decided to hook it up to the stereo so I could listen to my music and audio books. At first I just used a standard 3.5mm cable, but was getting the hissing noise, so I went to Radio Shack and purchased a ground loop isolator, but I am still getting hissing noise when ever the inverter is turned on. If I run the laptop off its battery, its crystal clear, but as soon as the inverter is turned on it turns into a mess. I've tried a 350 watt inverter and I also tried plugging it into the 1000 watt inverter I have installed, both had the same result.

Any Ideas?

I'm just trying to keep this simple since it is my work vehicle and I get a new one every 2-3 years.

**edge2k** · 01-17-2009, 12:03 AM

The cable is picking up interference from the inverter, if you can try a higher quality cable with a better shielding, orrr if your not to worried about the cable so much you can try and cut a small bit of the insulation off and if there is a shield, you can solder a wire to it and try grounding it.

Thats what i would try, but check the inverter first make sure it has a good solid ground and see if the noise increases or clears up when you move the inverter and the laptop power adapter away from the cable and radio.

=) hope it helps.

**lees40** · 01-19-2009, 12:38 PM

Would this also apply to my mp3 audio files starting to sound "choppy" all of a sudden since I had my 1000 watt power inverter installed? What happens is that every several seconds the play back will sort of "stutter" a bit, just enough to be annoying.

**PaulF** · 01-19-2009, 12:50 PM

I have a laptop in my work vehicle and decided to hook it up to the stereo so I could listen to my music and audio books. At first I just used a standard 3.5mm cable, but was getting the hissing noise, so I went to Radio Shack and purchased a ground loop isolator, but I am still getting hissing noise when ever the inverter is turned on. If I run the laptop off its battery, its crystal clear, but as soon as the inverter is turned on it turns into a mess. I've tried a 350 watt inverter and I also tried plugging it into the 1000 watt inverter I have installed, both had the same result.

There's nothing you can do about it. Inverters provide dirty power. They make boxy sine waves rather then pure smooth sine waves. When your laptop is operating off of these, they go all the way through to the speakers. You basically need to get a pure sine wave inverter to solve the problem. These are double the price of a regular inverter.

Would this also apply to my mp3 audio files starting to sound "choppy" all of a sudden since I had my 1000 watt power inverter installed? What happens is that every several seconds the play back will sort of "stutter" a bit, just enough to be annoying.

Is the source of the mp3 files connected to the inverter?

**lees40** · 01-19-2009, 12:58 PM

Originally Posted by PaulF

There's nothing you can do about it. Inverters provide dirty power. They make boxy sine waves rather then pure smooth sine waves. When your laptop is operating off of these, they go all the way through to the speakers. You basically need to get a pure sine wave inverter to solve the problem. These are double the price of a regular inverter.

Is the source of the mp3 files connected to the inverter?

Yes, it is a laptop connected to the inverter.

**PaulF** · 01-19-2009, 01:12 PM

Originally Posted by lees40

Yes, it is a laptop connected to the inverter.

If the laptop is on battery power and the inverter is on, I'm assuming Mp3's don't skip?

**lees40** · 01-19-2009, 01:13 PM

Originally Posted by PaulF

If the laptop is on battery power and the inverter is on, I'm assuming Mp3's don't skip?

I will try that in a few minutes and let you know.

**lees40** · 01-19-2009, 01:26 PM

Originally Posted by PaulF

If the laptop is on battery power and the inverter is on, I'm assuming Mp3's don't skip?

Here is what I just tested, and the results.

1. Inverter turned on, laptop running from inverter power. - Stuttering sound mentioned earlier.

2. Inverter turned on, laptop running on battery power. - Horrible static sound.

3. Inverter turned off, laptop running on battery power. - No issues.

**PaulF** · 01-19-2009, 01:46 PM

How is the inverter connected?

**lees40** · 01-19-2009, 01:50 PM

Originally Posted by PaulF

How is the inverter connected?

The inverter is wired directly to the car battery, via a relay that switches it on when the vehicle is running. In addition to the laptop, there is also a powered USB hub and Linksys router that get power from the inverter. I really appreciate any help you can provide. I am going to be off line for a couple of hours now, and will check again for your feedback after that.