[ICOM] dynamic mike

[Anders Janis SM4RNA]

Gary, I just checked the schematic. The mic earth do not have a series DC 
blocking capacitor. The mic earth is directley connected to the earth of the 
amp.

Jack I have posted a mod on www.mods.dk that brings up the gain to the same 
level as the IC-756 non PRO on a IC-775. I use my radio with Heil HC-5 with 
that mod and it works fine. Of course I use a DC blocking capacitor in 
series with the mic element.

I have never tried a Astatic so I do not know if the mod will be the 
solution or not.

/Anders


----- Original Message ----- 
From: "Gary P. Fiber" <gfiber at clearwire.net>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Thursday, December 07, 2006 11:14 PM
Subject: Re: [ICOM] dynamic mike


> Jack,
>
> The mic amplifier gain may be an issue but further there is a simplex 
> voltage
> applied to the mic pin, generally + 8 VDC.  Most dynamic mics I have seen 
> are a
> direct DC coupling from Mic input to Mic ground, there may be an issue 
> shorting
> the +8 VDC to ground with little DC resistance.
>
> Some of the Icom rigs do have a capacitor in the ground  mic audio ground 
> so it
> is signal not DC ground but I do not remember about the IC-775. A check of 
> the
> schematic will tell though.
>
> I am sure during my time at Icom I helped a few connect up dynamic mics 
> but
> can't remember about the low drive issue. I think Astatic makes an 
> amplified
> base for their mics which should solve that trouble if it is one.
>
> Gary K8IZ
>
>
>
>> Hello All:
>> I am new to the Icom Reflector.
>> I would like to use a Astatic model DA dynamic mike on a IC-775-dsp rig.
>> I am told that there is not enough gain in the rigs preAmp for a
>> dynamic mike.Is this correct ?
>> ----
>> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>> Icom FAQ: http://www.qsl.net/icom/
>>
>
>
>
> Gary P. Fiber K8IZ
> GROL PG-19-6691
> Washington State Resident
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/