[Icom] 756 Pro audio question

[Don Rasmussen]

Kelly Wrote:
> My question.  To me, some of the audio sounds "raspy" or "fuzzy".  I 
> realize this is a DSP rig where my TS850 is analog.  However, I've seen 
> lots of rave reviews about the audio in the 'Pro.  Is this fuzziness 
> normal?  It is especially noticeable on CW signals with the 500 & 250 hz 
> filter in.  And some signals tend to have more "fuzz" than others.  This 
> could also be entirely user error as there are so many settings on the 
> Pro.  One thing I have noticed is that using the NR fuction tends to 
> "smooth" out the fuzziness, although not completely eliminate it.

Hi Kelly and guys,

Kelly, your serial is very late, my one year old (original) Pro is in the
3000 series. As for the rave reviews for audio in the pro, that could relate
more to phone modes than CW. Still, the DSP CW filters seem very robust in
contests, possibly even better than a TS850.

As for the fuzz/rasp, that can be dialed out fairly easily by turning up the
CW PITCH control (775hz or better). I don't know why, but it helps. Also
make sure the NR and NB are off. The speaker is also hyper-critical, if you
try every speaker you have you will find that the signal is very loud from
some speakers and mixed in the background with others. I like the Drake MS4.


Even after increasing the CW pitch you will still hear a rushing sound with
the steeper skirted filters. (BFP on display) This can be unwelcome for
ragchews and can be eliminated by choosing the softer skirted filters. In
the original Pro that means selecting 600hz or wider then narrowing it down
as desired with the PBT controls. Finally, in quiet conditions you may
notice a "watery" effect in the background even after all of these changes.
I don't enjoy it so I set the RF GAIN at S3 and leave the preamp at 1. That
removes any traces of it and still leaves lots of gain in the receiver as
opposed to simply leaving the preamp off which leaves the receiver pretty
deaf. This setup is optimal for me and leaves nothing to be desired in
comparison with my best analog transceivers. 

For what it's worth, TenTec is saying that their new high end transceiver
has all of the fun of a DSP radio but without any of the DSP peculiarities.
I'll need to experience that first hand to believe it!

73,
de WB8YQJ