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Hi all,

I'm slowly getting my head a tiny bit around the impedance thing.
Unfortunately my funds cannot always follow my simple understanding.

For examle:
The palmer pms-02 and pls-02 are both passive splitters, the mic one has an input impedance of 200Ohm and the line one of 600Ohms.

What would happen if I used the line one (600Ohm) to split a mic signal?
Would I hear a loss in high frequency content?
Or would it mean I would have to turn up my preamp a lot more, thereby increasing the noiselevel?
(I can get a great deal on the line one)

As you can probably read between the lines, I'm trying to convert my limited physics knowledge of impedance into practcal audio knowledge.
Information I could find on the web.



moonbaby Wed, 09/13/2006 - 08:10

The difference between the "line level" and "mic level" splitters, whether passive or active, is not merely the load that they present to the input, but also their operating level. A mic level circuit and/or transformer will easily become "saturated" when the more substantial line level signal hits it. This will yield very nasty distortion artifacts. A line level input being presented a mic level circuit/transformer will not provide the gain necessary to properly amplify the weaker mic signal. Boosting the gain after the splitter will yield too high a noise level. You also have to take into account that a line level splitter has no need to provide phantom power to its source, so they aren't designed with that in mind. And, yes, there are issues with the frequency response changing depending on the source's rated impedance it "wants to see" and the actual load the input provides. But in lieu of the other factors already cited, that point is academic. So, better to stick with a mic level splitter if that's what you want to split up. The reason that the line version is so much cheaper is because there is no support circuitry for the phantom power, not to mention supply and demand.

moonbaby Wed, 09/13/2006 - 09:34

I would recommend contacting the various manufacturers of these products to get you started. Whirlwind, ProCo, Jensen Transformers, and Rapco come to mind. I know that Whirlwind offers some very good support. You might also look into live sound articles/documentation, as live and broadcast sound are the main users of this type of gear. Check out the Yamaha Live Sound Handbook (MIX Bookshelf), ProSound Web, and the book section of this website.