I happen to have a few 3M Peltor Comtac headsets with single comm connection.  One is a Comtac III, the other is a Comtac V.  I'd like to try using a headset with a Yaesu FT-891 in the shack, and thought I might try getting a Comtac to work instead of buying a Heil Pro7.

Any ideas on how to make this work?  I know the Comtacs are odd in terms of getting them to play well with non-mil radios.  I have one of the U-94 PTTs modified by Disco32 for using the Comtac with a Baofeng/Kenwood HT, so I figure somebody has played around with this.

Here is a good resource for you... pinouts/wiring for various microphones and radios.

https://www.qsl.net/g4wpw/date.html

Thx for that info Jupiter.

I reached out to the guys at Disco32 about this but they don't seem interested in discussing it.  I would have thought that .mil guys would have experience hooking up Peltors to various radios.  Then again, maybe they do have the experience and don't want to share. :(

I hooked a mic from an old helo helmet to my radio once years ago.  They are condenser mics and a bit more difficult than a plain old dynamic mic but it can be done.

Dynamic mics are simple; tip and ring / hot and ground / positive and ground, whatever you want to call it just wire it straight through.

Condenser mics are not so straightforward.  They require 5 VDC to the mic element to power it, but then a capacitor has to be put in the line going to the radio to block the 5 VDC from going into the audio circuit.  It isn't hard to do but a little tricky to do it right without causing problems.  The simplest way to do that would be to buy an adapter cable for your radio's mic connector to feed a condenser mic element.  Those sold for the Heil headsets would probably work fine.  The mic and headphone speakers plug into separate jacks on their adapter cable, and then there is a mic connector to match the radio.  They also provide a jack for a foot switch or hand switch if you want to use one.  I think they are around $20 and can save a lot of problems.

I suggest you call DX Engineering, explain what you are trying to do, and get some advice from them.

Your best bet is actually Heil or an audio specialist. Without doing a lot of research DXE will not be able to advise you well either.

DX Engineering is a Heil dealer and pretty familiar with the stock and options.  Maybe they can help, maybe not, but nothing lost by calling and asking.  I've gotten a lot of good advice from them in the past.

First of all, it's not a weird idea at all. It's more common for handheld radios, but not unheard of (ha, a pun! ) for desktop or mobile radios. Personally, for desktop use, I prefer a set of lightweight headphones like the Presonus HD7 and a desk microphone, but to each his own.

Second, does anyone think this is really hard or mysterious? Do you want to build an adapter or buy an adapter? Buying one might be hard as they are generally built for handheld radios. It would not be hard to get it mostly built:

1. Google "peltor y cable adapter". Here's a shitty airsoft one (a good one will cost you a mint).

2. Next, get a shitty airsoft PTT adapter for some random radio. Here's another example. Note the TP-120 pinout given in this Amazon listing, it might be important . The "U94" is the designation for the jack that the TP-120 plug goes into.

3. Crack open the PTT and rewire as required.

4. Chop off the radio plug and wire in an RJ45 connector for the FT891.

The advantages of this approach are twofold: you get nice molded cables and the mechanical design is all done for you.

Or you can go completely from scratch.

1. The two pin connectors on the Peltor are, for the male, U-173/U (aka MP-101, NSN 5935-00-888-5351) and the female, U-172/U (also mates with U-179/U, MP-101, and JJ-055).

Buy them lot's of places, or here and here.

RJ45's are, of course available anywhere. Cut up an Ethernet cable.

The microphone for your FT891 is a dynamic mic. No worries about electret mic's. Spec's and wiring diagram (click the "wiring" link) are here. That's the most important information right there, it tells you how to wire that RJ45 jack for PTT and mic connections. Easy peasy.

Note the impedance of 190 ohms and sensitivity of -78dB. The spec's for the standard Peltor boom mic's are here. Those mic's are actually a little more sensitive, which is good, and the 150 ohm impedance should be fully compatible.

Important question: exactly which boom mic do you have? Make and model? Legit Peltor or weak sauce airsoft?

eta: or just get a nice pair of Presonus HD7's and a Yaesu desk mic

Sell the extra Peltors and buy something purpose built?

It shouldn't be hard to sell them.

You mean something like this?  

Attached File

Thank you, that will get me started.  Comtacs are legit 3M.



Well that's certainly getting there!  How'd you make the Peltor PTT work with the HT?  I have that PTT (came with the Comtacs) but thought only the modded U-94 would work.

I’d be kinda neat to have a PRC-77 handset for my VX-8.

He wants to hook it up to a HF base station in his shack.

I have the comtac 6 with a disco32. Works perfectly with my yaesu vx7r and they make a ptt for the icom 705. The 705 has a button lock out, can be charged via 5v. Maybe give that a look if you were in the market.