Wiring a Balanced Microphone to the TS-590S Unbalanced Microphone Input

Using a balanced microphone with a transceiver's unbalanced audio input in the presence of RF fields can be a challenging setup unless you pay close attention to both ends of the microphone cable. Obviously, start with good quality connectors and microphone cable that is suitable for balanced line work. I get my connectors and balanced line mic cable at Parts Express and have had very good luck using this very durable cable with braided shield:

Part # 100-280


I would avoid cables that use spiral wound shielding or aluminum wrap shielding with a carrier wire as it’s easily damaged and not always reliable in the presence of an RF field.

When connecting a balanced microphone to the unbalanced mic input of  the TS-590S keep in mind that the front panel jack of the transceiver has two different grounds, one specifically for audio, and another for establishing chassis ground. With that in mind, when wiring up an 8 pin microphone plug for use with a balanced microphone, observe the following:

Kenwood uses pin 7 as the MIC (-) that is terminated inside the transceiver at the circuit board where the mic preamp is located. Solder pin 7 of your 8 pin microphone plug to the balanced lead you have selected for connection to Pin 3 of the XLR connector on the other end of your cable that mates up with your balanced microphone.

Kenwood connector pin 8 is the chassis ground of the TS-590S. Solder the shield of the balanced line microphone cable to pin 8 (the center pin) of your microphone plug. At the other end of your cable, the shield should be soldered to pin 1 of the XLR connector that mates up with your balanced microphone.

Kenwood connector pin 1 is the MIC (+) audio lead so select the remaining balanced lead and solder it to pin 1 of the 8 pin connector. At the other end of the cable, solder the MIC (+) audio lead to XLR connector pin 2.

The last step is the most important as far as keeping RF out of your transmit audio. At the XLR connector, solder a bare wire from XLR pin 1 to XLR pin 3, and then solder that to the XLR ground tab so the metallic XLR body will be bonded to pins 1 and 3. Bonding these three connections together at this point will keep the RF voltage potential on the various grounds at zero at the mic and will also guarantee that the metallic microphone body is at the same potential as the 590S chassis. The balanced twisted leads inside the wire will reject hum and RF and will be further protected by the coaxial shield that is connected to the 590S chassis with continuity right to the microphone’s metal body.
The picture below is probably much clearer than all the wording above. Note that this setup conforms to the industry standard pin connections for XLR wiring.


To avoid adding another path for RF to enter the front mic connector and also to keep things clean and simple, I elected to use the PTT connection at the back panel REMOTE connector (pin 3) to control the TX/RX keying for voice operation. As long as you have reasonable grounds at your station this should be pretty much bullet-proof as far as keeping RF out of your unbalanced transceiver’s microphone input.

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