Evenin' all. Just a quick (ish) update re couple of latest doings.
More Betterer Bluetooth and Pot-in-a-Box (aka 'DIN Amp' or pre-amp)
Don't worry Kubelik is in progress!
Bluetooth recap -
I have been using this 'Bluetooth adaptor' which has a daugter board as the ubiquitous (apparently) KRC-86B...
So the final plan was to pull the KRC-86 off the motherboard (which has a 5V regulator and connectors) and basically replace it with 'Bluetooth 4.1 5.0 Audio Receiver board' ... the chip is one of the JL AC19AP-1XXXX-25A4 series ...[latterly] I detected an artifact which I believe to be, what I call, 'capacitor mush'. There are DC blocking caps in the signal paths somewhere, but I haven't yet identified exactly where they are, but they are undoubtedly SMD. The whole thing is too involved anyway, there's a multiplexer chip (i.e., a solid state stereo selector switch), and at least one dual op-amp. (And 2 other 8-DIL chips with no markings.) The idea is that there is another, 'default', stereo audio input, but when the receiver establishes a Bluetooth connection, it switches over to Bluetooth audio. The module is intended for Bluetooth speakers, apparently. I don't need that much complexity and so then I found a different board, that just has audio straight out of the chip, via a couple of easily accessible caps.
Actually replacing it was going to be awkward but it can simply be connected - I found a handy plastic box and construction commenced -