Building Mic Cables for Connecting a Balanced Dynamic Mic to a FLEX-5000

There are two primary methods for connecting a balanced dynamic microphone (one that does not require phantom power) to the FLEX-5000 by using either the front 8-Pin Foster connector or the 1/4" TRS Balanced Line In input on the back of the FLEX-5000.

Both inputs will work, although using the 8-pin Foster connector provides a  20 dB mic preamp in the circuit whereas the Balanced Line In connection on the back does not.  

Both cables will need balanced microphone cable; two conductors (wires) *twisted* with a shield. For this example, the two wires will be labeled white (positive/mic+) and blue (negative/mic-). The cable shield is ground. The wire gauge needs to be 24 AWG.

If you want really good mic cable, then look at mic cabling called "star-quad" cable.  This cable is a  four-conductor-shielded configuration can best be thought of as two twisted pairs twisted together.  Using four small conductors in place of two large ones allows the loop area of the cable to be further reduced and its rejection of electromagnetic interference (EMI) is improved by a factor of ten (20 dB). 

Here is a link describing Star-Quad microphone cabling: Q. What’s special about star-quad cable?

Here is a resource to get some of these cables

Standard Mic cable:

Star-Quad cable:

8-Pin Foster Connector (female) to 3-pin XLR (female)

pin 5 on Foster --- [ground/cable shield] --- XLR pin 1
pin 8 on Foster --- [mic+/ white wire] -------- XLR pin 2
pin 7 on Foster --- [mic- / blue wire] --------- XLR pin 3

NOTE: Connect the cable shield to the shell of the 8-pin Foster connector too.


8-Pin Foster Connector (female) to 1/4" TRS plug (male)

pin 5 on Foster --- [ground/cable shield] --- 1/4" sleeve
pin 8 on Foster --- [mic+/ white wire] -------- 1/4" tip
pin 7 on Foster --- [mic- / blue wire] --------- 1/4" ring


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