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Re: [TenTec] proper caps for Omni V?--> Sanyo Oscon

To: Rick Denney <rick@rickdenney.com>, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] proper caps for Omni V?--> Sanyo Oscon
From: Joe Roberts <jroberts@io.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Wed, 05 Mar 2008 17:44:08 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
There is WAY WAY too much AF gain in the Omni V. A factory recommended 
fix was posted on this board recently by Don K6RV on 16 Feb 08.

There is also some overdrive of the product detector going on. W3TS mods 
address that issue. Big help with IF noise and resulting AF intermod.

While re-capping your rig, try Increasing the SSB AGC time constant caps 
   to avoid pumping. I did this before recapping the rest of the board 
and noted an increase in definition and clarity, as well as less jumpy 
AGC, but I think the quality enhancement was a fresh spunky cap at work 
rather than the change of value.

There are a number of overlapping issues with the Omni V that all impact 
  listening enjoyment. AF gain distribution is one, but excessive 
digital noise which can be fixed by good caps and the above-mentioned IF 
gain issue are others.

Replacing the stock 1st IF sideband filter with the 2.7 INRAD is also a 
fabulous improvement which goes beyond mere bandwidth considerations. I 
have never seem this adequately explained, but the ears don't lie (and 
even if they do, how can you tell?). Others have commented on this 
effect, so it is not just me.

All I can say is that it is extremely worthwhile to "retread" the good 
old Omni V. With the fixes, it sounds as good as anything I've ever 
heard...and I have always been a obnoxious snob about good RX audio.

Of course, the basic performance is outstanding too...and with the mods 
you can finally enjoy it.


73 Joe N5KAT







> I'm hoping that doing so will address an audio quality issue that I
> have on my V. When I turn the AF knob past about 8 or 9 o'clock, the
> audio amplifier clips, as we've discussed before. Using a clean
> external headphone amp to equalize normalize the amplitude, I've been
> able to observe that clipping on my scope. I can turn it way down, and
> turn the external amp up, and there is no clipping, though the audio
> noise floor rises, too (usually to no ill effect because of band
> noise).
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