[Amps] Soft Start

[Kim Elmore]

Yes, more accurately a step-start. Regardless, that’s reassuring to know!

Kim N5OP

"People that make music together cannot be enemies, at least as long as the music lasts." -- Paul Hindemith

> On Dec 27, 2017, at 06:25, Jim W7RY <jimw7ry at gmail.com> wrote:
> 
> Soft start (I call it step start) does reduce filament inrush current. As long as it's on the filament transformer primary.
> 
> Which it is in the SB200, SB220, TL922, L4B and TenTec Titan... And many others.
> 
> 73
> Jim W7RY
> 
> 
> -----Original Message----- From: Kim Elmore
> Sent: Tuesday, December 26, 2017 9:58 PM
> To: Warren Volz
> Cc: amps at contesting.com
> Subject: Re: [Amps] Soft Start
> 
> A related question. Once long ago I read that power cycles are very hard on filaments. Is that also the case with soft starts, or does the soft start reduce the thermal shock issues?
> 
> Kim N5OP
> 
> "People that make music together cannot be enemies, at least as long as the music lasts." -- Paul Hindemith
> 
>> On Dec 26, 2017, at 21:08, Warren Volz <warren at warrenvolz.com> wrote:
>> 
>> I’d recommend a step start with fuses. I have w7ry’s board in my sb220 and the fuses saved me from a bad tube once already.
>> 
>> -Warren
>> 
>>> On Dec 26, 2017, at 8:59 PM, Jim W7RY <jimw7ry at gmail.com> wrote:
>>> 
>>> I recommend 10 Ohms. I use 2 resistors and 2 relays. There are fuses in series with the resistors to protect them.
>>> 
>>> Why would a cap blowing up cause an issue with a step start circuit?
>>> 
>>> Again, I use 2 resistors and 2 relays on a small circuit board.
>>> 
>>> See:
>>> 
>>> https://www.ebay.com/itm/282765541853?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
>>> 
>>> 73
>>> Jim W7RY
>>> 
>>> 
>>> 
>>> 
>>> 
>>> -----Original Message----- From: Arnie Pfingst
>>> Sent: Tuesday, December 26, 2017 8:31 PM
>>> To: amps at contesting.com
>>> Subject: [Amps] Soft Start
>>> 
>>> Once upon a time, i had a capacitor explode upon start up. I've heard stories for and against adding a soft start circuit to my amplifiers.(Some say 20 ohm resistors, and others say 30 or 40 ohm.) That and the price of replacement tubes. In my case i have two TL 922a amps using 3-500z tubes.
>>> Both set up on 240vac. What do you all have to say here. Thanks
>>> Arnie
>>> 
>>> 
>>> 
>>> Sent via the Samsung Galaxy S8 Active, an AT&T 4G LTE smartphone
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>> 
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps 
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps