[R-390] 390A audio

[Bob Camp]

Hi

If you are going to do the diode load pick off be *sure* you have a  
high impedance amplifier input. It's one of those "higher is always  
better" kind of things.

Audio is going to also depend on the performance and condition of  
your IF filters. R-390'a are getting old enough that bad filters are  
showing up with some regularity.

If the filters look good and the audio still has problems then start  
working back from the diode load towards the antenna. IF stage and  
AGC problems can also show up as audio issues.

Bob





On Sep 3, 2007, at 4:11 AM, Dan Cotsirilos K9DTC wrote:

> http://www.r390a.com/html/diode_load.html
>
>
> Dan K9DTC
>
>
>
> ----- Original Message ----- From: "Rasputin Novgorod"  
> <priapulus at yahoo.com>
> To: <r-390 at mailman.qth.net>
> Sent: Monday, September 03, 2007 12:11 AM
> Subject: [R-390] 390A audio
>
>
>> I'm not very happy with my audio. I'm no expert at
>> this, but looking at the schematic, I wonder if I couldn't
>> pickoff low level audio from the "Diode" pin 14 at the
>> back panel and feed it to an external high impedance input
>> audio amplifier & speaker?
>>
>> I've read about the cap mods.
>>
>> Sincerely
>> /b
>>
>>
>>
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