[TenTec] Yamaha CM500 headset and Orion II

[Jim Brown]

On 12/16/2013 5:46 AM, Richards wrote:
> I chance to disagree with just this one minor point ... and offer my 
> Omni VII and Orion II as an example.   On the Omni VII one has to turn 
> the AF-GAIN down to nearly 1 or maybe 2 before it does not cause the 
> ALC light to come on all the time.   Similarly on a pair of Orion IIs 
> - one mine and another in a contest shack - although it was not as 
> drastic on that rig as it is on the Omni VII.

Something does not compute. The function of the AF-GAIN pot is to adjust 
the mic output level to the rig. The numerical setting (dial setting) 
does not matter. What matters is the audio drive level that AF-GAIN 
produces at the output of the audio stage.

>
> Still,  I venture to recommend a voltage divider or simple L or T pad 
> to reduce the inherently high output which cuts it down to 
> approximately what the rig sees from a typical dynamic mic cartridge.  
> This gives the ALC more headroom to do its magic.   I believe crowding 
> it down to very low AF-GAIN kinda crowds the ALC so that it can be 
> difficult to set -i.e., it is either all on or all off,  and on my 
> Omni VII, the mice is either on or off by the 2% setting and ALC is on 
> all the time at that setting.

Nope. ALC action occurs AFTER the audio gain stage that is being 
adjusted by the AF-GAIN control . The only indication that an attenuator 
(pad) was needed would be audible distortion on the transmitted signal, 
which would be the result of the audio stage being overloaded by the mic 
(and clipping at the input). That is VERY unlikely unless the Ten Tec 
engineers are a LOT dumber than I think they are.

>
> Thus, it is my opinion, an attenuator pad is a good idea, and makes 
> the mic appear to the rig more like a dynamic mic (which I believe it 
> is designed to expect most often.)

Lessee -- I'm an EE by training and profession, and you're a retired 
attorney. Last I heard, you hadn't done extensive study of electronics 
to catch up. I wouldn't consider give legal advice -- heck, even though 
I know a helluva lot about acoustics, I'm not trained in that field and 
know my limitations, so I don't give advice on acoustics either.

73, Jim K9YC