[TenTec] 566 v3.029 and 707 Regal mic

[Bob McGraw - K4TAX]

I had a 707 and sold it.  May buy another one just to try again.   My 
preference and best sounding of all mikes is the 709A.

I don't specifically recall if Tentec actually changed by design the source 
or output impedance of the 707 mike or perhaps maybe corrected a published 
specification.  I suspect the latter.

 In any event, I can't imagine producing a dynamic mike today which has a 
source impedance of 50K ohms.   That would require the transmitter audio 
input to present something like a 500K ohm load or greater.  I don't recall 
a current rig on the market today that can provide correct loading for a 
mike having a source Z of 50K ohms.

>From a very reliable technical audio source I quote:   "Matching microphone 
and pre-amp impedances to the same value (power-matching) is not desirable 
since it reduces both the level and the signal to noise ratio by 6dB. For 
dynamic and condenser microphones, the preferred preamp input impedance is 
generally about ten times that of the microphone output."      ref  - 
http://www.sweetwater.com/expert-center/techtips/d--08/19/2004

With the spec of >10K @ 1KHz for the Orion mike input, this would then 
expect one to use a mike having a source or output impedance at some value 
less than 1000 ohms. This is the same as the Omni VII and the Eagle and the 
Argonaut VI which have the same Microphone Input Specification being >10K @ 
1KHz.


73
Bob, K4TAX

----- Original Message ----- 
From: <Rsoifer at aol.com>
To: <tentec at contesting.com>
Sent: Saturday, December 01, 2012 11:20 AM
Subject: Re: [TenTec] 566 v3.029 and 707 Regal mic


> In a message dated 12/1/2012 4:53:56 PM GMT Standard Time,
> jruing at ameritech.net writes:
>
>
>> Subj:Re: [TenTec] 566 v3.029 and 707 Regal mic
>> Date:12/1/2012 4:53:56 PM GMT Standard Time
>> From:jruing at ameritech.net
>> Reply-to:tentec at contesting.com
>> To:tentec at contesting.com
>> Sent from the Internet
>>
>>
>>
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