The AM Forum

I have a Peavey dynamic mic which I've connected to the IC-718 using Heil's CC-1 XLR I cable. I tried this configuration on the air and received audio reports of  "choppy audio". Is it possible to use a professional condenser or dynamic mic with this radio? If it is possible, how is it done?

I've asked around QRZ and a Yahoo group for my IC-718. I didn't get a straight answer on what's supposed to be the bridge between my rig and my mic. I was hoping that the AM audio experts on this forum could lend me some clue.

If this is on AM it's not the mic causing the problem. The problem is being caused by either the swr shutdown circuit which is very sensitive or the ALC on voice peaks. I ain't figured it out yet. I do know that running the mic gain on the radio above 50 makes it totally unusable fo AM.

Try it on SSB and see ifn you get the same reports.

I was getting that report on slopbucket.

"Choppy audio" isn't particularly helpful.  COuld very well be the SWR foldback circuitry is reducing the xmit power if your antenner is presenting an SWR higher than 1.5 to 1 or so.  Or the mic gain is set too high and the ALC is kicking in, reducing the power.

I've run a Shure dynamic microphonium with a Kenwood TS-50 - no problemo - should be the same case with the Icom.  Try reducing the mic gain or power output or whatever control the thing has....

Running VOX??

If the 718 has a 4 to 8 volt dc on the mic line (probably does)...

You need a dc blocking capacitor in line.......

Yes..... there is a .33 uf blocking cap in the stock mic.

Right click on the photo link and "save as".
It looks better on MS photo editor at 75 to 100% size.

A neat little function on cw is; the frequency up/down buttons work as a keyer paddle when in cw. You'll need to select "paddle on" in the main setup. Takes some getting use to but works good in a pinch.

From what I have seen on the yahoo IC-718 forum, they use the auxiliary audio input on the back of the rig with a preamplified mikes.   THe preamped D-104 works good that way.    However, you need the weird connector for the audio and PTT on the auxiliary input.

Yep, sure enough, there is power on that mic line for the electret element,,,

Put a .33 to 1uF 'lectrolytic in series with the mic line....

Use a "non-invasive" method first... to test...

I had to do that with my 706 when I used a dynamic.....
Crappy audio without it......

Yes, I was running VOX.

Well then.... running VOX... that screws up most anyone's audio....

Not a fan of that myself.....

But, try running PTT not VOX, see if you get the same reports, if not, adjust the vox gain + delay....

If you get the same reports, then fix the mic....

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Probably the number one reason for "choppy audio". Unless you can talk in monotone, VOX can be a real pain. Ever notice on SSB how many hams, who use VOX, start their transmission with "Ahhhh" or "grunt grunt" just to kick the transceiver on.

Interesting. I thought I needed a preamp for this mic.

Hi, i see ur online right now. STOP using that mic until you put in a blocking cap or you will overheat and kill the 8vdc reg in the radio. More to come in another post, just wanted to catch your attention.
 

#2

Lol.. Just wanted to get that one up quick. I killed the 8vdc reg in my 756 by running a dynamic on it with no cap to block the dc short the element shows to the radios' preamp and it was absolutely NO FUN to find it and replace it. The reason it sounds harsh is because the dc on the mic hi line is working the dynamic element like a solenoid. It needs to be blocked with a cap, and that will straighten the audio out. Icoms are a little low in the mic gain dept anyway, so even after the blocking cap, you may find the audio ok at best, but not great.

The preferred method is to run a decent outboard pre and jack that right into the balanced modulator on the back of the radio. this bypasses ALL the internal microphone crap and it will sound FB. You'll need a decent pre and probably an EQ to get it done right. A lot of guys use the w2ihy box with great success.

With my 756, I run the audio as stated above, into the balanced modulator. I use a cheapo Marshall v63 condenser mic and an ART Pro Channel. (mic pre/power supply, compressor limiter, and 4 band para EQ, all tube based and in one 19" box for under 300.00) and it works great and I don't have any of the RF problems of separate pieces daisy chained together.

Food for thought.