[Elecraft] K2 - Strange Problem ?

[Vic Rosenthal]

Stewart Baker wrote:

> The amplifier only draws about 1mA, however because of noise on the 5A line,
> mainly from the LED bar graph I have had to heavily decouple the pre-amp supply
> to stop the noise from being superimposed on my speech.
> 
> What I think is happening is that this decoupling is affecting the rise time of
> the 5A line which is used for the MCU reset amongst other things.

Why don't you do this (must be viewed in fixed width font):

5V -------\\\\\\\----|----> to preamp
          large R     |
                     ---
                     ---  cap for decoupling
                      |
                     ---
                     ///

You will get better decoupling and isolate the capacitor from the 5V rail.

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco