Had some time to mess around with this problem before the supper bell and figured out at least what was causing the problem.

I started by getting several other new pots out of my stock of such items, a couple of other speakers and three clip leads.

After disconnecting the pot with the wired on connector proceeded to try several other pots starting with a 10K pot, three clip leads from volume connector on the bitx40 board to the pot and gave it a try.

Bingo! Works just fine, no "squeal" at a low volume setting.

Tried another, works just fine.

And another, works just fine.

Tried the original three pots which gave me the problem and all worked OK.

All this with 15" long clip leads strewn willy nilly on the workbench.

The problem turns out to be the be the three pin connector with six inches of wire. This was one of connectors and wire included with the kit. Replacing the wire and connector fixed the problem.

I don't know what the problem with the connector and wires is, looks OK to the eye but I guessing maybe some form of oxidation on one or more of the wires and/or connectors and/or ????? I have already put the problematic piece in the trash and moved on. I may just go dig it out of the trash and do a forensic dissection and see if I can figure out the actual failure mechanism.

Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.

Thank you one and all for your suggestions.

cheers, Graham ve3gtc

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Hi Raj,

I found that my problem was with the connector I had used for the volume control. There was some form of oxidation one the spring "pins" in the connector that was causing the audio stage to oscillate when the volume control as at or near zero ohms.

A different connector and wires and all was better.

I have seen some strange things before but this was a first.

cheers, Graham ve3gtc