[minima] Re: Linear Output Filter Switching

  • From: Wayne McFee <nb6m@xxxxxxx>
  • To: "minima@xxxxxxxxxxxxx" <minima@xxxxxxxxxxxxx>
  • Date: Thu, 6 Feb 2014 10:25:10 -0800

Hi Dan,

Sure you can definitely use single poles and lower value caps for lower power.  

But it doesn't cost much more to build the output filters for higher power than 
you think you are going to use, so that you don't have to rebuild them when you 
want to switch out your lower power amp for another one.

Actually the 200V caps should be good for up to 20-25 Watts, for 50 watts they 
should be higher yet, say 500V units.

But it is all up to the individual builder, and this is really a neat project 
for experimenting and hacking.  

I'm really enjoying all the comments,


> On Feb 6, 2014, at 9:46 AM, Dan Reynolds <on30ng@xxxxxxxxx> wrote:
> Great work Mark. That will get me started for sure. My Si570 should be here 
> today. 
> Wayne, I think it's a good idea to double the contacts for higher power but 
> I'm probably not going to have a power amp higher than 10 watts or so.
> 73
> Dan -- KB9JLO
> https://sites.google.com/site/on30ng/
>> On Thu, Feb 6, 2014 at 5:52 AM, Mark G0MGX <mark.g0mgx@xxxxxxxxx> wrote:
>> Hi Team
>> I've done a bit more work on the output filter switching using a 4028 (which 
>> arrived today!).
>> The wiki is updated:
>> http://www.hfsignals.org/index.php/Final_Output_Filters
>> Including a link to a simple sketch to try and illustrate how it works and 
>> enable others to prototype the ideas as I have.
>> There will be more on this topic from me....
>> Mark
>> G0MGX

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