Mic/Preamp Impedance

deejaysly · Post by **deejaysly** » Wed Oct 22, 2003 7:04 am

Does anyone here know what impedance spec I should be looking at on a mic to match a preamp?

For example, the preamp spec sheet says it has 2Kohms Input Impedance (XLR). The spec sheet for the mic has two impedances, namely Nominal Impdance (spec'd at <100ohms) and Load Impedance (spec'd at >1Kohms).

Which mic impedance relates to the input impedance of the preamp input?

And then what would the other mic impedance spec be for?

Hoping that someone knows.....

Music Manic · Post by **Music Manic** » Wed Oct 22, 2003 8:04 am

Yes 200 ohms is the standard for capacitor mics now and the preamp has a large impedance.Remember lo goes to high,lo goes to lo,hi goes to hi but high never goes to lo.
You shouldn't have any worries.The only problem you may have is the choosing of the mic cable,which should come with mic.Hi inductance cables cause problems.
Hope that helps!

deejaysly · Post by **deejaysly** » Wed Oct 22, 2003 9:36 am

Thanks for your reply Music Manic.

So do you mean I should be looking at the nominal impedance of the mic when trying to match it to the input impedance of the preamp? (..and ignore the load impedance in the spec sheet for the mic)

And when you say too much inductance in the mic cable can screw things up, how do you mean? will I hear it in the sound or does it affect the level that I get out of the mic?

Music Manic · Post by **Music Manic** » Wed Oct 22, 2003 9:51 am

Yes cheap cables could cause HF rolloff if the inductance is bad.It is the capacitance caused by the signals.
What mic are you using and where is it going?

deejaysly · Post by **deejaysly** » Wed Oct 22, 2003 1:49 pm

The mic is a Behringer B2 Pro and the preamp is an ART Tube MP Studio V3.

Music Manic · Post by **Music Manic** » Wed Oct 22, 2003 3:07 pm

Yes read the manual for mic and you need the phantom power supply from the preamp.You need a male to female xlr mic cable.
The cable is attatched to the mic input(Hi-Z)of the pre-amp.I can't see if the pre-amp has phantom on and off button.If it does switch it on.Make sure everything is plugged in before you switch pre-amp on.
Ciao!

Post by **garyb** » Wed Oct 22, 2003 7:30 pm

those items should work well together.as previously noted,the cable is possibly the most important item involved in good sound,but also the most overlooked.get at least a quad conductor cable for recording your important tracks.monster pro or studio pro or zoalla would be excellent step-ups.it's pretty amazing what difference cable will make(and how much that can cost).

Immanuel · Post by **Immanuel** » Thu Oct 23, 2003 10:16 am

The load >1kOhm impedance means, that the impedance of your preamp (load) should be atleast 1kOhm. The generally accepted rule is, that the load should always be atleast 10 times higher than the "sender" (my word).

deejaysly · Post by **deejaysly** » Fri Oct 24, 2003 1:48 am

I wasn't sure whether it was to do with that (maximum voltage transfer) or something to do with the load the mic puts on the phantom power supply.

Thanks for clearing that up Immanuel.