On Sat, 2010-01-30 at 10:01 -0800, Jim Brown K9YC wrote:
> On Sat, 30 Jan 2010 10:21:34 -0600, Dr. Gerald N. Johnson wrote:
>
> >I have a DSP-599. The 599zx is different and may work better. The 599
> >does a great job of adding selectivity, though you run a risk of strong
> >signals outside its passband running the receiver AVC and so chopping up
> >the signal you want to copy. That's always a problem with selectivity
> >after AVC. The 599 does have a automatic leveling function that works
> >decently.
>
> >As for noise reduction, I've never found it to dig a signal out of the
> >noise that I couldn't detect without it, but the noise reduction does
> >increase the S/N of signals that I can barely detect without the 599 in
> >use.
>
> I bought a 599zx to use with my Omni V. I also tried it with a TS850. I
> was generally disappointed with the result with both radios, and sold it.
> My observations are pretty much in line with Jerry's. I also found the
> Time Wave's audio performance pretty weak -- that is, by the time you get
> enough level to drive headphones, it's adding audible distortion.
>
> 73,
>
> Jim K9YC
>
I sometimes use a passive and switchable low pass filter in the speaker
circuit to trim off the audio stage distortion harmonic products. The
only problem is it takes even more audio output to get a reasonable
listening level. It might need an impedance matching transformer to put
more voltage to your headphones. But the DSP599 doesn't have a great
audio output stage, as I recall, a LM386 that's not good for many watts.
73, Jerry, K0CQ
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