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[AMPS] L4B Soft-Start SS-400

To: <>
Subject: [AMPS] L4B Soft-Start SS-400
From: (
Date: Wed, 10 Feb 1999 23:54:36 -0500

On Wed, 10 Feb 1999 06:21:09 -0800 "Will K6NDV" <>
>Isn't the reason to install the SS-400 to save the ON/OFF switch in 
>the L4B?
>I have heard some failure stories and also that the switch in not 
>any more.
>Thanks Will,  K6NDV

After 20-30 years switches fail but not as frequently as some of the soft
start circuits.An amp turn-on failure is usually sufficient reason for
serious cussing.
I have a few hundred rocker switches from the NCL-2000. Folks tell me
they fit in the Drake and SB-220.

73  Carl   KM1H

>-----Original Message-----
>From: <>
>To: <>
To: <>
>Date: Tuesday, February 09, 1999 11:01 PM
>Subject: Re: [AMPS] L4B Soft-Start SS-400
>>On Tue, 09 Feb 1999 21:42:01 -0500 David Humbertson
>><> writes:
>>>Hi All,
>>>I recently installed the Harbach SS-400 soft-start module
>>>in my L4B and would be interested in hearing from others
>>>who have done the same. Looks like my tubes may not be
>>>fully cutoff as I am seeing a bit of plate current and a small
>>>amount of neg grid current in standby - works fine otherwise.
>>>My 120 volt line reads 100.3 in SSB with the module in and
>>>125 with it out. No one else that I know of has experienced
>>Sounds like a defective module Dave.  Besides, why bother using one
>>anyway? The L4B PS has sufficient inrush lag as designed, plate and
>>filament. If you are using an external heavier duty replacement xfmr 
>>switching to 1N5408 diodes in the HV will more than enough handle 
>>inrush. Costs less than a failure prone add-on.
>>73  Carl  KM1H
>>>73, Dave - W3NP
>>>Ft. Ashby, WV
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