Mike In to Line in Balance

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bigkim100
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Mike In to Line in Balance

Post by bigkim100 » Fri Jul 26, 2002 10:05 am

I've seen this scematic a million times, but never paid attention to it, now I need it. Just need the simple circuit that will "pad" the mike input of a recorder, to accept line in signals.
PLEASE!!!, I really need it.
[email protected]
THANKS
Kim..The man with the cute little girls name...and Frankensteins face and body.

Gregg
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Re: Mike In to Line in Balance

Post by Gregg » Sun Jul 28, 2002 3:42 pm

You can buy an Impedance matching transformer cable at any electronics or music store to allow the adaption of an unbalanced, high impedance signal (line level) to a balanced, low-impedance level (mic level). This only cost around $25.00 cdn. This is your best bet.<p>[ July 29, 2002: Message edited by: Greg ]</p>

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Externet
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Re: Mike In to Line in Balance

Post by Externet » Sun Jul 28, 2002 11:36 pm

Hi Kim.
Connect ANY potentiometer extreme terminals to the line level source.
Connect the wiper terminal and common ground to the microphone input jack.
Near one extreme of rotation, when the wiper is almost ground, the voltage division will match levels.
If you want to replace it with 2 fixed resistors, measure the potentiometer branches at the satisfying setting.
Miguel
- Abolish the deciBel ! -

bobsRAC
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Re: Mike In to Line in Balance

Post by bobsRAC » Mon Jul 29, 2002 2:34 am

The divider circuit will match the impedence correctly if the pot's total resistance is equal to the line impedence and the wiper is set to the mic's impedence, but the conversion will disipate the difference as heat. The impedence matching xfmr will transfer the power much more efficiently.<p>If you want it done cheaply, go with the pot. If you want it done correctly, use an xfmr.

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Externet
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Re: Mike In to Line in Balance

Post by Externet » Mon Jul 29, 2002 12:46 pm

Hi BobsRAC<p>I have no clue why you may want to transfer the power efficiently.
What has to be done here is exactly the opposite; to dissipate the extra line level power of about 0dBm to get about the -40 dBm micropower the microphone input needs.<p>Miguel :)
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bobsRAC
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Re: Mike In to Line in Balance

Post by bobsRAC » Tue Jul 30, 2002 2:05 pm

Yes, most definetly...<p>Ignore the xfmr and get a pot... :)

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