Has anyone run into this with an Inverter?

[John Diel]

I have a pretty good Power Inverter in my vehicle. 800W/1600W peak power and has worked well in the past.

However, I get a really bad hum from this when attempting to play DVD's while the Laptop is plugged in. I suspect power line noise from the Inverter itself (dirty power).

Does anyone know of a decent Power Conditioner or RF filter that would eliminate this noise? The inverter works well for simple power and the like, but when attempting to entertain the family on long trips the hum is quite annoying.

-- John

 

[David Drummond]

Try plugging in a power strip into the invertor and then the computer into the power strip, see if that helps.

 

[John Diel]

I haven't put it on a "good" power strip, but currently on a 6 outlet strip. Right now, I'm looking at possibly adding a power conditioner used in audio setups, but it's a fairly expensive route to go just for a lousy DVD set up on the laptop.

I'm also looking at either Monster or Acoustic Research power strips that claim to have some power conditioning or at least filtering built in. Another option would be a UPS, but again, it gets a little expensive.

 

[David Drummond]

Is this hum something new or always been there?

 

[John Erwin]

I suspect the problem may actually be with your laptop's power supply more than the inverter; it may be letting some of the invertor's AC couple through and "ride" on it's DC output. Square waves such as those produced by most inverters can be more problematic and noticeable too. If this is what is happening there is no amount of filtering on the AC side that will stop this; it must occur on the DC side instead. Still, you can try to rule out other noise factors by using a decent filter strip such as those made by Tripp-Lite or Monster.. take note that regular "surge-protectors" do little to remove noise.

It might be easier to consider using a DC-DC converter for powering your laptop instead, these are sometimes sold as "universal laptop power supplies" and may come with a 12v plug to power it. I've been using such a device for some time now with excellent results.

If you want to go the filter route instead it will mean either modifying the Laptops power supply or putting something inline between it and the laptop; preferably something that is designed to work better with square waves.

 

[John Diel]

I appreciate the info guys. No, the "hum" is not always there. I've run into it with other "dirty" power sources. One that even bleeds through a very nice Mackie Mix Board. Usually, this ends up being a bad ground line, something letting a few volts through. However, that's on a straight AC line. The Inverter is a bit different. So I'll go the "cheap" route first and try a good surge protector/line conditioner. I may even end up swapping inverters for one that has the modified sine wave. We'll just have to see where this goes.

Again, I appreciate the info.

-- John