[TenTec] early morning questions

George, W5YR w5yr@att.net
Sun, 19 Nov 2000 12:38:22 -0600


I also use the ProSet and have for some time now. I use it with an
IC-765, a Kachina 505DSP and an IC-756PRO. I have not observed the hiss
that Vince mentions with any of these radios.

I think it is off the mark to assert that the Proset "introduces a white
noise type of low level hiss . . ." The headphones do not and cannot
introduce anything since they are a passive device.

I think that what Vince is observing is that the high-frequency response
of the ProSet is such that he is able to hear the "white noise" coming
from his receiver. As he mentions, another headphone with a more
restricted frequency response does not allow him to hear the noise.
Evidently, the TenTec has an extended high-frequency audio response
which Vince is able to hear with his ProSet.

So, my point is that the ProSet should not be faulted as a contributor
of unnecessary noise; rather it merely reproduces the noise which is
coming from the signal source.

I have not observed this hiss effect with any of the three radios I
mentioned above. This is due partly due to my hearing loss at the higher
audio frequencies and partly due to my use of external audio filtering
most of the time. Nonetheless, I have no difficulty hearing and
understanding speech even under adverse conditions.

I find that the comfort and convenience (boom HC-5 mic) of the ProSet
are outstanding; it is my only headphone now. I highly recommend it. I
have not used the Yaesu headset that Vince recommends, but from his
comment, I am sure that it is a very good one, especially for CW. 

My approach to hearing CW is to do the necessary filtering in the radio,
etc. and not rely upon the headset to contribute its own response
function. The problem with headsets that have a relatively narrow
response is that they can tend to introduce ringing and other aural
artifacts. This also applies to speakers with sharply peaked response.
These factors can be controlled properly with modern filters such as the
DSP filters, but are seldom dealt with correctly in audio transducer
design.

72/73, George   W5YR - the Yellow Rose of Texas      NETXQRP 6	       
Fairview, TX   30 mi NE Dallas in Collin county	     QRP-L 1373
Amateur Radio W5YR, in the 55th year and it just keeps getting better!
Icom IC-756 PRO #02121 (9/00) Kachina #91900556 (12/99) IC-765 (6/90)


Vince & Betty wrote:
> 
>       In my experience, I have found that the Heil Pro Set introduces a
> white noise type of low level hiss when operating CW with narrow filters in
> line (use of the LP or NR DSP facilities reduces or deletes this situation).
> Perhaps this additional internally generated noise is due to the wider audio
> pass band of the Pro Set headset.
>       I currently use the Yaesu YH-55 headset which, because it is very
> sensitive and requires little audio gain to produce adequate volume, does
> not introduce any hiss when using CW filters. It's chief advantage to me is
> that it appears to have a limited audio passband which peaks around 700-800
> Hz, perfect for CW reception. Although not quite as comfortable as the Pro
> Set, the YH-55 has been an excellent CW headset over the years.

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