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@Jonny69
Slight diversion. Key bit of information I left out was that the JLH build will almost certainly end up in the living room. I still needed a small amp for the spare room so I did indeed indulge in a cheap eBay kit. They’re all much of a muchness, based on Chinese clones of long-obsolete ICs and there are loads to choose from. I settled on a stereo pair of TDA2030s, mainly because it was one of the kits that came on a single board and I didn’t want the hassle of mounting two boards and having to buy extra stuff like a dual pot of the volume control. But also because it was class AB, through-hole, it had convincing-looking heatsinks designed in and it had bass and treble onboard. This quick build was pretty much all parts bin stuff or recovered/scavenged parts. £5.53 delivered for the amp, a couple of £ for the RCA jacks and speaker posts and I’m pretty sure the rest was all stuff I’d pulled out the bin.
As usual, my old nemesis the hum was in full swing. First thing I tried was more PSU smoothing, by bodging in a couple of extra smoothing capacitors, but it became obvious that it was where I’d remote mounted the pots for volume, bass and treble. The wires I used were unshielded and were picking up noise when I moved my hand near them. I thought about doing something properly but in the end just rolled them in aluminium foil from the kitchen and earthed them. It’s not completely got rid of it but most of it is gone.
That all happened because I wanted some ventilation out the back so put the potentiometers on wires instead of directly on the board. Hindsight. Probably should have split out the TDA2030 ICs on their heatsinks instead.
Anyway, it’s class AB so it sounds ok. Probably kicks out about 5-6W per channel but that’s all I need. Stuck some knobs on from the PSU case from the JLH build and that’s all it needs.
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