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[Amps] SG-500 ALC Interface to Kenwood TS-480HX

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Subject: [Amps] SG-500 ALC Interface to Kenwood TS-480HX
From: "Jim Thomson" <>
Date: Wed, 27 Jan 2016 17:39:43 -0800
List-post: <">>
Date: Mon, 25 Jan 2016 18:19:13 -0500
From: Ron Youvan <>
To: amps <>
Subject: Re: [Amps] SG-500 ALC Interface to Kenwood TS-480HX

    Larry Dighera wrote:

> Given the SG-500's ALC control signal is +1 to +5 VDC, and the Kenwood
> TS-480HX's ALC signal expects -7VDC, how have others interfaced these two
> pieces of equipment?

   I don't know, but a 9 Volt battery might do it.

   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.

## A  9 vdc battery fed across the far ends of a 50k pot.  Then take the 
output, between
wiper and positive end of pot.   Then you can vary the output of the mess  from 
0-9 vdc,
and its all negative Vdc..then  feed that negative 0-9 vdc  into your TS- 480 
HX ALC jack.
Then NO alc connection from xcvr to amp. 

##  Then you can set the  PO of the TS-480HX.....if it has an adjustable PO  to 
what ever the
amp requires.   Then dial up the pot till po of the amp just drops a tiny bit.  
 At that point, you can
scream all you want..and never over drive the AMP.   You can also turn the PO 
on the xcvr to max,
and  tweak the pot for desired drive into the amp. Same deal, scream all u 
want, and u cant overdrive the amp.

## this  2nd scenario works better, since there is no time lag in developing  
ALC  voltage in the xcvr.   You have already
developed it  via the 9 vdc battery and pot.   The only drawback to using the 9 
vdc battery + pot is..... if you whisper into
mic you will have reduced po from the xcvr.    In normal operation it works 

##  an alternate method that may well work is to use a SS  DC to DC  converter. 
  Then you could  feed the +1  to +5 vdc
from the amp.... into the input of the DC to DC converter,  the output side 
will be either 0-5 vdc positive..OR  0-5 vdc
negative. The dc to dc converter isolates the input to the output side.    In 
your case, the output side will have its positive
bonded to chassis of xcvr, with negative going to alc jack of xcvr.   

Jim   VE7RF
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