Now, I have absolutely no problem with Mr. Bob Heil, or the fact you might want to buy one of his headset specially made for the Icom IC-706MKIIG. But, if you don't need the up & down buttons, and want to save probably $60, then continue on down this page.
The headset I built for my 706 is made from a Motorola single earpiece headset I found on closeout at Lowe's for a total of ...$4.00! It was originally priced around $20.00. You can also use computer headsets, but be sure to read the requirements just below!
You need to make sure the headset you use has separate grounds for the speaker and mic lines, and a "2 wire" electret mic element! A three wire mic element will not work! (Three wire element has audio hot, audio ground, and DC in...). You need at least 4 wires total, a hot and sheild for the speaker circuit and hot and ground for the mic circuit!
The IC-706 provides DC power for the electret mic element up the audio hot line. As long as you use a 2 wire electret element, no dc blocking capacitor is needed, as you need the 8V DC for the mic to operate.
NEVER, NEVER, NEVER wire a non-electret mic element directly to the mic jack of a 706...you will burn out the 8V regulator!
Next, we need to hook it up to the rig so it will work. So we whack off the end, and on the earphone side, we put a 1/8" stereo plug, which can have the speaker hots wired together, or to only one side, either way will work.
On the mic side, we have to do a little more. Here is a general schematic on how to hook up an electret mic (which is what ALL 706's use) to the modular jack on a 706:
(You can wire a floor PTT switch this way, and still have a hand switch...)
(This is the "direct" way to wire it with no adapters or plugs...)
Now when I first built this, I built a fancy adapter out of a pill bottle. But, it is just in the way. So here is what I wound up with:
The modular mic connector is about 4-6" cut off a regular RJ-45 networking cable!
And remember that pill bottle I spoke about? Well this isn't it:
What the PTT is built from is an old diabetic testing strip can! And the switch is just a simple NO SPST switch of your liking.
And the usual disclaimer: I am not responsible if you goof up and burn out the 8V regulator in your 706. Make sure you wire correctly!
Depending on the audio characteristics of the electret mic element, you will need to adust the mic gain, compression, and possibly the transmit carrier offset (Menu "Q6" on the 706MKIIG).
The speaker circuit should be simple enough to figure out, but, if you have a single earpiece headset, wire the hot to the tip of a stereo 1/8" plug and the shield to the ground. If it is a dual earpiece, wire one hot to the tip, one hot to the ring, and shield(s) to ground. It does have to be plugged into the "PHONES" jack on the front of the 706.
Folks, that is about as easy and cheap as it gets. And I get good audio reports with it, and most can't tell if I am on the headset or the hand mic! It's comfortable, and keeps fatigue down when operating. Even works good on VOX too!