[TenTec] orion with 2.055 firmware -- headphones?

[Ron Castro]

The audio output chip in the Orion is the TDA1013B by Phillips, which is 
adequate for the job although not THX Hi-Fi by any means!  You can see all 
the specs and performance data at:

http://www.semiconductors.philips.com/acrobat_download/datasheets/TDA1013B_CNV_2.pdf

The chip is designed to deliver 2.5 Watts into an 8 Ohm load with 13.8 volts 
power and distortion under 10%.  It will deliver closer to 4 Watts into 4 
Ohms, and lower power into progressively higher impedances.  Distortion 
specs are actually quite good if the chip is not pushed to the limit.

I find that the speakers levels are quite loud using a Kenwood SP-31 for the 
external speaker, which is a fairly efficient unit.  Lesser efficiency 
speakers will make the acoustic levels lower, so the key is 4-8 Ohms (lower 
is better, but beware of too low, or the power dissipation will be too 
high),  and high efficiency enclosure design to get the most volume in the 
room.

Ron N6AHA

----- Original Message ----- 
From: "ROBERT CARROLL" <w2wg at comcast.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>
Sent: Tuesday, March 14, 2006 6:33 PM
Subject: Re: [TenTec] orion with 2.055 firmware -- headphones?


>I have been a little irritated by the audio performance of the Orion using
> the TenTec external long-throw speaker.  As far as I know this is not
> firmware related.  It MAY be due to the power handling capability of the
> speaker, or it may be a limitation in power capability of the audio output
> stage.  It certainly has a lot to do with the ambient noise level in my
> shack.  In any event, using the speaker,  the audio sounds normal till the
> audio gain is cranked up to a certain point, perhaps half scale on the 
> audio
> indicator.  Then the audio starts to distort as though something is 
> breaking
> into overload.  Listening to the signal over phones doesn't show the
> distortion.  In any event the Orion doesn't seem to have the ability to
> "belt it out" to the extent of an ICOM 756 or an old beast like an FT900. 
> I
> had read of similar issues with the FT1000MP which apparently has a wimpy
> op-amp audio output which was subject to self destruction if you demanded
> too much off it for too long.
>
> In any event the Orion has enough audio oomph with the speaker for most
> situations here, but when the linears are grinding away with some furnace
> noise in the background, I could use more "guts."  Of course I never do 
> any
> serious operating when the speaker is in use, but I wonder if anyone else
> has noticed a tendency to this audio breakup at moderate to high volume
> levels?
>
> Bob W2WG
>
> -----Original Message-----
> From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
> On Behalf Of K4IA at aol.com
> Sent: Tuesday, March 14, 2006 8:34 PM
> To: tentec at contesting.com
> Subject: Re: [TenTec] orion with 2.055 firmware -- headphones?
>
> You are correct.  The new version has regressed back to the occasional
> scratchy distorted audio that was present in early versions of the
> software.  I
> found that turning the volume control up and down again  usually will fix
> the
> problem.  Seems worse at narrow bandwidths and NR on  but that is just my
> gut
> feeling.
>
> K4ia  "Buck"
> Fredericksburg, Virginia USA
>
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