[1000mp] FT-1000MP back ground hiss. CW Cap Mod

[WD8ARZ]

Your pretty good ... hi hi and a very good point. Mine did have the older
value, and the intent of the mod did perform as expected and explained for
its purpose. With out it and no Dsp, I would copy the cw with some spectrum
band noise. With the cap I would copy just the cw. Same when I did or didn't
use the Dsp. Thus I choose to stay with the option that gives me the choice
of either. Once the cap is in, there is no choice.

What is actually going on here is very common to audio amplifier design
choices. Designers tend to match for mode of operation, users tend to push
for hifi on one extreme or barely pass the chosen mode on the other. There
is a lot of room in between.

I remember I used to modify audio amps in my hf rigs to suit my tastes.
Increase the series coupling caps to improve the low frequency response, and
reduce the value of, or remove shunting caps for higher frequency response.
This cap mod is like one of those .... it is a shunting cap and reduces high
frequency pass band for the audio at that portion of the circuit.

The MP is the only hf rig that I have had that I have not changed audio amp
components.... yet. I might one day in fact do some of the opposite going on
in these discussions .... for am and ssb, I may wish to raise the highs a
bit more than they are at, and compensate as needed with the Dsp.... I have
some high frequency hearing loss from my Air Force days around fighter jets,
so sometimes like to boost the highs a bit more than some do.

Well, looks like we have covered all the bases on this topic once again
..... enjoyed the refresher, and sure love this wonderful group!

73 from Bill - WD8ARZ
wd8arz@ix.netcom.com

----- Original Message -----
From: "Billy Cox" <aa4nu@ix.netcom.com>
To: <1000mp@mailman.qth.net>
Sent: Wednesday, May 01, 2002 13:37
Subject: Re: [1000mp] FT-1000MP back ground hiss. CW Cap Mod
>
> >I put one in with a switch. Ran many many tests of CW with this
> >cap switched in and out, and it does make a difference, at the
> >audio level. But it doesn't make a difference on my rig or to my
> >ears any more than choosing the Dsp settings. Thus I have
> >chosen to leave this mod out, and my selection options open.
> >Some who are not using matched narrow cw filters, might object
> >to the Dsp being set tight, and in that case might prefer the cap
> >mod instead. I don't have that issue here.
>
> Seems like there's a note in the INRAD instructions, saying to check
> the actual value of what the MP has ... one of mine had 1 value stock,
> the other had another value ... so on RIG A, it made a difference, yet
> on RIG B, it did not seem to be needed ...
>
> Perhaps that's why you observed your results ?
>
> 73 Billy AA4NU