Maestro / PR-781 mic plug compatibility

Jack H

My PR-781 works fine when plugged directly into the 6400.

However, when plugged into the Mic 2 jack on the Maestro, using the same cable, it only works if I pull out the mic plug partway. In this case it sounds as good as when plugged into the 6400, however the connection is not solid since it's partway out and the audio cuts in and out if the cable is bumped.

Is there an adapter needed to use the PR-781 with a Maestro to allow the plug to be inserted properly?

Tim - W4TME

You will need to get a TRS 1/8" plug and wire tip to MIC+, leave the ring "floating" (no connection and connect the sleeve to MIC- and ground.

Jack H

Thanks for the reply, Tim.

Seems odd that the Maestro mic input design is not compatible with the 6400. I was hoping to just switch the PR-781 mic cable back and forth between the two.

The FHM-3 acts the same way as the PR-781. So does that mean the same home-brew adapter as you described will also work for the FHM-3 when using the MIC-2 input on the Maestro?

Interestinlgy the CM-500 headset works fine as is. It's apparently wired differently.

73,
Jack
W9JH

Bill N3HQB

Flex used to sell an XLR to 1/8" phone cable wired for the Maestro. I have one; it works.

This one is currently on the Flex website...

https://www.flexradio.com/products/inrad-m-f-cable-for-3-5mm-flexradio-6400-6600/

You might check with Flex or Inrad to see if it is wired correctly for the Maestro Mic 2 input, or DIY as Tim suggests.

Bill N3HQB

Additional comment: The logo "Cable Creation" is found on the XLR cable I bought from Flex, mentioned in my previous post.

Jack H

Thanks, Bill.
I'm getting the parts together for a DIY adapter so I can use the existing cable, which works fine when plugged directly into the 6400. The adapter will have a female 3.5 mm TRS connector on one end to plug in the existing cable and a male 3.5 mm TRS to plug into the Maestro MIC 2 jack. I will wire according to Tim's recommendation. This way I will be able to keep the existing cable in-place on the mic boom and just use the adapter with the Maestro when using the PR-781 there.
Appreciate the info.
73,
Jack
W9JH

ka9ees

Check the model number of the cable. It's probably available on Amazon for a third of the cost.

Ed KA9EES

Jack H

Ed,
I got the PR-781 cable I'm using with the 6400 from Amazon. Correct about the price and it works fine when plugged into the 6400. However, as mentioned in the original post above, the cable plug is not compatible with the Maestro MIC 2 input due to the difference in how the respective audio-in jacks are wired. Problem should be resolved once I receive the parts to make a simple adapter for use with the Maestro.

The FHM-3 has the same incompatibility issue as well when using the MIC 2 input on the Maestro.

Why they designed the two Mic inputs (6400 vs. Maestro) that way is puzzling. But that's how it is.

Jack
W9JH