[TenTec] 1.732 Headphone Distortion w Strong Signals

[Mark Erbaugh]

On Mon, 2004-12-06 at 06:41, Larry Rockfield wrote:
> While others have lost audio tone with Version 1.732, I have headphone audio 
> distortion from the main receiver on strong local signals in the range of 
> 59+40 dB and above.  The speaker has no distortion under the same operating 
> conditions.
> 
> Prior to Version 1.732, the S-meter stopped in the vicinity of 59+35 dB,
> regardless of signal strength.  With this new version, the meter will
> actually hit the stops at 59+60 dB.  Ten-Tec has: "Fixed S-Meter routine to
> correctly show signals greater than +35 dBm."
> 
> The headphones are Heil Pro-Set Plus and additional resistance padding is
> often used to help suppress QSK keying clicks.  So, I doubt the headphones
> are the problem. Master Reset and RAM-CLEAR have not helped.  Adding 
> attenuation or reduction of RF Gain will clear the audio.

I have observed this also with my 1.372 update, although I notice it on
signals in the S9 or over range. The headphones here are a pair of
Kenwood HS-5's that have been modified for stereo operation. I also have
an external Stereo L-Pad volume attenuator that I use because I find
that even with the main AF gain at the smallest level (above off) that
the audio is sometimes too high for my quiet shack.  However, I have
observed the distortion with the attenuator in line or with the
headphones directly connected.

For reference, I regularly participate in the 40m TT SDR net on Sunday
evenings. With 40 meter propagation the way it has been lately, I end up
using the headphones a lot. This week, with version 1.372 installed, I
noticed that a lot of the stronger signals just didn't sound as good as
I had gotten used to from many weeks of listening using 1.371. Many of
the weaker signals sounded fine.  I tried all sorts of adjustments (RIT,
PBT) without much success. I didn't find that RF gain reduction helped,
but I don't think I tried the attenuator.

I'm glad someone else noticed this. I was starting to think that
something had happened to my Orion.

73,
Mark