Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: NSB_Chris on March 28, 2019, 08:25:12 pm

Title: Wall power inrush current limiter and filter
Post by: NSB_Chris on March 28, 2019, 08:25:12 pm

Does anyone bother with adding a filter (0.1uF) cap across the AC mains leads and a current limiting thermistor on the neutral lead?  I see this on some of the more modern schematics.  The amps I have built so far were vintage clones and I just ran the AC input straight through the switch and fuse to the PT.  Anyone think it is worth the extra trouble?

Title: Re: Wall power inrush current limiter and filter
Post by: shooter on March 28, 2019, 09:01:38 pm

at the top of this page there's a search, had a pretty good discussion ~~1yr ago?

Title: Re: Wall power inrush current limiter and filter
Post by: NSB_Chris on March 28, 2019, 09:16:09 pm

Can you provide a link to the thread that you are referring to?  I did a google search earlier and just tried to search this forum but I don't seem to find anything directly on topic. 

Title: Re: Wall power inrush current limiter and filter
Post by: shooter on March 29, 2019, 09:37:46 am

this isn't the one I was thinking, but it has links to "fixes"
http://el34world.com/Forum/index.php?topic=23036.msg246947#msg246947

most forgo any fancy wiz-bangs.  I have put .1uF on the left side of bridge, even used them on the right side  :icon_biggrin:.
I believe ppl have tried MOV's, step start etc. at the end of day they probably do little and provide yet another thing that can break