On Tue, Jul 25, 2006 at 04:15:25PM -0700, Tree Tyree N6TR wrote:
>
> K8BB writes:
>
> > Can anybody offer an alternative solution for somebody who still has
> > very-wide-frequency hearing? I am not really looking for a "ham radio audio
> > filter" as much as I am looking to improve the poor-quality audio coming
> > from the audio amplification stage of my receivers.
>
> I have the same issue - and still hear things others can't at the high end.
>
> Two solutions I have seen:
>
> 1. Back before we had audio filters, there was a circuit in the older
> handbooks
> called something like a crud-o-ject. It was a passive audio filter that had
> some big inductors in it - and really did a good job eliminating hiss.
I use a very simple R/C low pass filter. It uses one resistor and one
capacitor. I do not recall the values I ended up using I just played
around until I was happy with the sound.
I did look at the noise with a software audio spectrum analyzer on my
computer to see where the hiss was - it was well above the audio passband of
the receive audio as I recall - this also gave me a starting point for
component values.
http://www.qrp.pops.net/filter1.htm
and
http://www.muzique.com/schem/filter.htm
might be useful - I am sure there are other sites with information
if you do a search.
--
George Fremin III - K5TR
geoiii@kkn.net
http://www.kkn.net/~k5tr
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