so anyway i finally got it working after like three weeks of staring at a breadboard and questioning my life choices. its a direct conversion receiver for 40m, basically following the NorCal design but i swapped out a few parts because i couldnt source the originals locally and i was too impatient to wait for mouser. the SA612 mixer is doing its thing, i think, the audio out is going into a little lm386 amp stage i tacked on because the headphone volume was just too low.

the thing is picking up SSB stations but everything sounds kinda underwater, like there's a lot of hiss and the selectivity is obviously pretty rough. i know direct conversion has that mirror image problem but honestly im just happy it does anything at all at this point. wound my own toroids for the bandpass filter using some T50-2 cores i had laying around, not sure i got the turns exactly right but the SWR on the input looks okay-ish when i check it.

anybody else go through this phase where youre not sure if the noise is the design or your construction? because i cant tell if im hearing real stations through garbage or just garbage lol

yeah that underwater sound on a DC receiver is pretty normal, especially with the lm386 - that chip adds its own noise floor and if your gain staging isn't right it'll just amplify everything equally including all the hiss. what bypass caps do you have on pin 7 of the 386? a lot of builds skip or undervalue that and it makes a big difference. also the mirror image thing you mentioned, on 40m that's gonna be rough without some serious front end filtering. the T50-2 is the right core for that freq but the winding count really does matter, even being off by one turn can shift the resonance enough to hurt you. if you have a dip meter or an antenna analyzer you can at least check where your filter is actually peaked.

keep at it though, a working DC receiver from scratch is more than most people ever build

omg i went through the exact same thing with my first receiver build, i used a different mixer chip but same vibe. the hiss drove me crazy for a week before someone told me i had a ground loop between my power supply and the audio section. stupidly simple fix but i never would have found it on my own. is your audio ground tied back to the same point as your RF ground or are they kind of floating separately on the breadboard? breadboards are notorious for this kind of thing, once i moved mine to a copper clad board with a proper ground plane it was like night and day honestly