alright.. so pretty much a copy and paste from FSB (am a member there too) but thought it may be useful here, and also someone here may be able to help too..
I built this using the original (reversed) file, so turned my ICs inside out (
) and got nothing, but the lm386 got warm
so I scored some more lm386 and started again with my own layout... built it and got nothing.. no sound at all..
I made the preamp and power amp modular.. easier to troubleshoot, and if I want I can swap the power amp out for something bigger maybe
the lm386 in the power amp are both getting pretty hot.. not melting yet, but I've not left it on very long cos I think they will if I leave it too long..
so, I disconnected the power amp and put the preamp into my ruby. I got a farty sound and only on full gain..
audio trace got it to the first opamp with good signal as far as pin6
as of pin 7 it was the awful farty sound.. kind of like a badly biased fet.. so I pulled out the LEDs and boom.. works awesome..
so a) do I need the LEDs in there (remembering I have zero theory knowledge so if they're vital, then .. um.. :blackeye )
and b) why would the LEDs cause an issue?
I noted that whilst they're both 3mm red LED, one is physically slightly larger than the other (maybe 0.5mm? but still nowhere near a 5mm LED).
thanks in advance
oh.. and layout and PCB are attached if anyone wants it, but bear in mind the power amp is as yet unverified and the preamp sounds like poop with the LEDs I had in there