Try a 4 ohm speaker - solved the problem for me!

De VK2AHF Syd

On Mar 27, 2017, at 8:29 AM, Graham <planophore@...> wrote:

I tried a second one and had the same behavior.? I will dig through my junk box and see if I can find another to try.

I am not sure how a pot that has dead zones on one or both ends would cause this type of behavior.

cheers, Graham ve3gtc

On 2017-03-26 21:05, Ken wrote:

Try a new one. I found that mine had dead zones at both ends of travel. Replace with a log or audio taper.

73 Ken VA3ABN

On Sun, Mar 26, 2017 at 5:04 PM, Graham <planophore@...> wrote:

Yes.

On 2017-03-26 20:55, Ken wrote:

Graham

Are you using the original volume control that came with the Bitx40?

73

Ken VA3ABN

On Sun, Mar 26, 2017 at 4:51 PM, Graham <planophore@...> wrote:

Good day all,

I have been messing about with my Bitx40 SMD on an off for a couple of weeks working towards getting it mounted in a case.

I have removed C113 across the LM386 pins 1 and 8 to reduce the gain, makes a big difference. Problem is that I get a high pitched "squeal" or oscillation at very LOW volume setting; turning the volume up a bit more and it disappears.

I have spent some time searching the archives for similar posts and fixes but just haven't managed to find much that is relevant.

Ideas?? Better bypassing on the power lines to the LM386?

Speaker is smallish 3" diameter generic 8 ohm speaker.

cheers, Graham ve3gtc