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[AMPS] ALC considerations with SB-200 and TS-430S

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Subject: [AMPS] ALC considerations with SB-200 and TS-430S
From: (km1h @
Date: Fri, 20 Mar 1998 10:26:27 EST
On Thu, 19 Mar 1998 17:23:02 -0600 KE3OK <> writes:
>Hi Gang,
>I just received my spiffy _new_ SB-200 amplifier today.  I'm using a
>TS-430S as an exciter.  The 430 requires -8 to-10 VDC for ALC.  After
>searching through the Heathkit manual I can't find anywhere that 
>states the
>ALC voltage of the SB-200.  Does anyone know?  Do I dare fire up the 
>and try to take a voltage reading from the ALC jack?  Any help will be
>appreciated.  BTW, I won't be putting the amp into service for a few 
>till I receive my soft key kit from Harbach electronics.  Thanks to 
>all in
>advance and 73,

I would not even bother using the ALC  Al.  Instead do some testing and
find out where you start running into gain compression. With the TS-430's
very touchy requirements for low VSWR it may not be the same band to band
and the SB-200's less than ideal input network. 
I have found that the 60-70W range is where the ratio of Watts in vs out
start to drop. 

Run it there, keep the Ig in the white range on the meter during tuneup
and do not let SSB voice peaks exceed 1/2 of the keydown Ip.

As far as age, you can check date codes on the tubes (if original),
electrolytic caps in the HV and bias supplies and the plate blocking
That is a fine little amp and everything is happy at the 600W output
level. It is possible to get 800W + out but the PS, tubes and band
neighbors will complain. 

The only mod I would recommend after the SoftKey is to add a 20-25 Ohm
20-25W  HV surge resistor. It can be installed below deck utilizing an
existing screw location and one of the perforated holes. One resistor
(enamel WW; not cement), two small ceramic or bakelite stand-offs and you
are done.

Excuse any duplication of others replies; my E-Mail is batch mode and I
only check it a few times a day. 

Enjoy,  Carl  KM1H

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