Author Topic: Simple device to eliminate impedance mis-match/grounding.  (Read 6195 times)

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Offline wuhu_software

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Simple device to eliminate impedance mis-match/grounding.
« on: December 31, 2006, 06:16:34 PM »
Here is a link to instructions for producing a simple device that sits between your weather radio and your computer's sound card line input.

This may eliminate problems with hum or other audio quality issues (other than bad reception).

http://home.comcast.net/~wuhu_software/EliminateHum/

Let me know if it works for you.

Offline SLOweather

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Re: Simple device to eliminate impedance mis-match/grounding
« Reply #1 on: December 31, 2006, 08:01:53 PM »
If the construction ability or time to do so is a factor, you can also get one of these from the Shack, for about 5 bucks more. I use several in our whole house audio network and for my stereo streaming scanners. Just use one of the cables for one audio source.



Link

Offline wuhu_software

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Re: Simple device to eliminate impedance mis-match/grounding
« Reply #2 on: December 31, 2006, 11:34:56 PM »
I saw that one as well. The only problem is that if you have mono 1/8" jacks, you need a couple of convertes (RCA to 1/8). It is amazing how much they charge for those little converter plugs!

There is a version from Crutchfield Audio that has 1/8" stereo jacks as well. If you are dealing with mono again, you have to buy converters that jacks back up the cost.

Thanks.

Offline wuhu_software

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Re: Simple device to eliminate impedance mis-match/grounding
« Reply #3 on: January 01, 2007, 11:26:59 AM »
FYI, from another forum.

> I had another question for you.
> Do those inline ground isolators perform the same
> function as the transformer you specified (see links below)?
> My guess is that they would not deal with the impedance mis-match.

The specs are pretty vague but what I gather from the descriptions, the Radio Shack and Wal Mart units are the same and are designed for line level connections. Note the Radio Shack disclaimer about not hooking up to speaker lines. They are probably high impedance 1:1 transformers. The Crutchfield one looks like it is designed to match a headphone jack (relatively low impedance, less than 1 watt). Hard to say what the output is designed to match to. Jim

Offline SLOweather

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Re: Simple device to eliminate impedance mis-match/grounding
« Reply #4 on: January 01, 2007, 12:18:21 PM »
For the plug n play crowd, Rat Shack as a couple of 6' impedance matching dubbing cables.

42-2152 has 2 1/8th inch mono connectors.

42-2461, 1/8" Phone Plug to RCA Plug

They used to have a similar impedance matching 1/8" to RCA adapter, but I can't find it in the catalog anymore.

Offline carterlake

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Re: Simple device to eliminate impedance mis-match/grounding
« Reply #5 on: January 01, 2007, 04:26:55 PM »
Ew! Weekend project!

Davis VP2 6153; Weather Display (LIVE w/ Ajax); Quickcam for Notebooks Pro; Boltek w/ Nexstorm; GRLevel3; live NOAA Radio

Offline ncpilot

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Re: Simple device to eliminate impedance mis-match/grounding
« Reply #6 on: January 02, 2007, 08:55:52 AM »
Yeah, all ready for a quicky project, went to RS, and they didn't have the transformer--so now I have to wait for it to be shipped to me... now it'll be a next weekend project...
Marc
Wilmington, NC
"Monkey Junction Weather"
Davis VP2 wireless, WeatherLink