Hi
I built an audio amp a few years ago, which consists of a toroidal transformer, a couple of independent unregulated 30V power supply modules and a couple of circuits built around the TDA2030. The circuits for the latter are pretty much the reference circuit from the datasheet for a single supply.
When I first made it, it hummed like billy-o. I fiddled with a bit, to no effect, and it then went under the bench for want of time and enthusiasm.
So, 15 years later I pulled it out from under the bench. Still hums; time hasn't improved it. I'd really like to get it working properly before I bin the TDA2030 in favour of something made this century.
Can you give me some ideas about what bits to connect to what, to shut the damn thing up? It's mounted in a metal case which is connected to mains earth and the signal leads are shielded. Plugging a signal source (my mobile phone, which I consider quite brave!) into it actually quietens it a fair bit.
Thanks
John