[TenTec] Using a Yamaha CM500 headset with TT Orion II - advice needed!

Jim Brown k9yc at audiosystemsgroup.com
Wed Apr 8 08:17:11 EDT 2015


On Wed,4/8/2015 2:22 AM, Steve Ireland wrote:
> My current set-up isn’t working (sounding) well and the best thing seemed to be to ask for some advice.

I'd guess that you're not using enough bias. Elecraft and others use 
5.6K between V+ and the mic.

You may also be wearing the mic too close to your mouth. It will sound 
better if you don't "close-talk" it. That will also reduce the level -- 
like RF, sound drops by 6 dB for a doubling of distance.

I wear my CM500 mic about 2-3 inches above and to the side of my mouth. 
This prevents bass build-up from close-talking, reduces the level a bit, 
and, more important, allows me to drink coffee and have an occasional 
munch. :)

That 470/220 ohm pad may be the cause of your distortion -- the mic 
probably wants to see a higher Z load (like the 5.6K resistor). You also 
probably don't need the cap. Check the schematic -- I'd be VERY 
surprised if there isn't one inside the box at that point. Remember that 
electret mics have been commonly used in ham radio for a couple of 
decades, and rigs are built to expect them.

I don't know the Orion, but Ten Tec was born of an engineer from the pro 
audio world -- he started Ten Tec when he sold Electro-Voice -- and they 
have always built radios that are quite tolerant of a wide range of 
mics. I've used pro mics with my Omni V and they sounded great.

73, Jim K9YC


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