diyaudio is pretty good, but it is hard to avoid the audiophoolery/just plain wrong-ness sometimes, though,m it is pretty good as far as that goes for an audio forum.
I'll have to disagree about the phoolery there. head-fi - now THAT is fool of audiofulls (uhm, ok, the other way around)
I won't spend any time there since its the blind leading the blind. cannot stand the ignorance and the 'sales' oriented nature of that forum. if you dare offend the holy iec cable salesman or the oxygen-free skin-effect silver wire guys, you get banned. that forum exists to separate fools from their money.
but diyaudio has actual engineers who work in the field and have a lot of name recognition and respect. designers of op-amps (linear, ti, etc) are there, as are world class amp and digital audio designers. people produce boards and do peer review of their designs. its a great site and there are not many 'phools' there. at the end of each year (around october) there is an event that everyone looks forward to called 'burning amp' (lol) and we get together to do demos, talks, exchange info and have a few beers at dinner when its all over.
there are a lot of junk audio sites but diyaudio is one of the best and most trusted ones for non-BS info.