Alright, time for a follow-up: I've added two 47nF (0.094uF total) ceramic caps, one 330pF ceramic cap, one 10uF electrolytic cap and another one 100uF cap across the DC input. Unfortunately, the prob

Thank you so much for your help Woody! I'll try to get my hand on a small ceramic cap and let you know if this resolved the problem. I'll also try to salvage the ferrite sleeve from an old cable. I'll

Thanks Woody :D Would adding a very small capacitor (nano/pico order) help as well? Or would this be too small to make any difference? And another question, does anyone know any MacGyver way to make s

I have some 100uf 50V on hand, added one across bitx40 dc socket, unfortunately the problem persists. I don't have any small caps right now, tomorrow I'll add a small cap and let you guys know if this

Alright, I'll try with a 1000uF capacitor, first I'll measure the output voltage with the capacitor between + and gnd lines of the supply output, then I'll give it a try with my bitx by soldering the

Wait a second, wouldn't soldering a large cap on a switched power supply create an overvoltage? As far as I remember, switch-mode supply units create low voltage by switching higher voltage on and off

I'll try to solder some caps to the power socket in bitx, some large ones nd some small ones for fast response. Maybe this will help.

Found 3 other pairs of headphones (nokia, motorola and some no-name headphones), the problem persists. However, I also found another wall-plug power supply, this one with a ferrite choke and rated 12V

I'm running the whole kit at 12V 3A from a wall-plug type of supply. The headphones are 23ohm apple headphones. Where would I exactly solder the 10ohm and 0.1uf?

@Raj vu2zap The problem is at any volume

@Ian Reeve the problem remains.

I tried unplugging the volume control completely, the problem persists

Please help

Fun fact, when I start to touch and move around the brown wire from volume control knob, I can hear local FM radio station.

Hi! I've just finished assembling my Bitx40, and when I turn on the radio, I hear a terribly loud noise (link to listen below). The radio works fine, because I can hear some operators behind that nois