[Elecraft] K3 LPF add-on filter

[Joe Planisky]

Hi James,

It's been some time since I bought and installed the LPF, and since  
it's not something you can put in and take out easily I can't comment  
on whether later firmware changes have reduced high frequency  
artifacts. The artifacts I was hearing back then were the aliased  
audio around the 12 kHz D/A clock, which the LPF pretty much knocked  
out.

The difference when I installed the filter was subtle, but noticeable;  
I still have SOME hearing left in the 12 kHz range :-)  I would say  
it's worth installing if either you hear the high frequency artifacts  
and they bother you, or you just want to keep your rig up-to-date with  
the latest mods, perhaps for resale reasons down the road.

Installation is pretty straight forward.  A sharp knife will do to cut  
the traces, I don't think you should get in there with a Dremel tool.   
One twitch and you could do a lot of damage.  I used an Xacto knife  
with a new blade and it was almost disturbing how easily the traces  
were cut!

73
--
Joe KB8AP

On Nov 15, 2010, at 7:25 AM, James Sarte wrote:

> Good morning Elecrafters!
>
> It's been some time now since the K3 LPF add-on filter board was  
> released.
> I've been contemplating purchasing one since its debut as I've  
> noticed in
> the past hi-frequency DSP artifiacts, especially when listening with
> headphones.  However, as time passed and firmware improved, I don't  
> seem to
> hear so many of the things I thought I heard before.  Perhaps my  
> hearing has
> changed as well - who knows?
>
> So, with that said - what are people's opinions now on the LPF  
> module?  Is
> it still worth the purchase?  Can a noticeable difference be heard,
> particularly on SSB with the filter installed?
>
> Finally, for those who performed the install themselves, what did  
> you use to
> cut the two traces?  Will a box cutter work or should I use a dremel  
> cutting
> wheel?
>
> Tnx,
> James
>
> -- 
> 73 de James K2QI
> President UNARC/4U1UN
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