Repurposing an old Android phone

(Originally posted on the RetroMat site in May 25, but sits better here).

For some time, I've been looking for a way to play my digital media through my Onkyo 'hifi' receiver from 2006 which has no USB port or SD card slot. I like the machine - it sounds great, is solidly-built and as well as a  CD player, has a radio, including MW, which I use for receiving distant stations. We have a Chromecast Audio that can be connected to it for on-line audio streaming. In all other respects, it meets requirements and I'm in no rush to replace it.

(I tried using an old QNAP NAS system, but it was a faff. IIRC, I was able to use it from our TV, using twonky, a now defunct standard, but would have had to move the receiver to the TV in order to connect the two and that wasn't convenient. Plus the TV won't play flac files. I think I tried using the NAS from my phone and casting from there, but couldn't find a way to stream from the NAS and instead had to download files. After that, I just gave up).

Years ago, when I had an Android phone with external storage, I'd connect the phone directly to one of the inputs. Since then, I've had hand-me-down iPhones and can't do that and my digital media has been restricted to my laptop.

There are impressive looking machines from Brennan. In time, I'd like to rip (losslessly) my entire CD collection, so one of these could make sense. However, they are bulky and somewhat over-specced for my needs: first I already have a CD player in the Onkyo, second I can rip CDs on a PC, and third, I don't really require all the high-tech connectivity they provide.

I could use a modern mp3-type player, but don't want or need a high-end device from the likes of Astell & Kern, or FiiO. Sony Walkman's are within my budget, but you have to pay up considerably if you want a decent amount of (non-expandable) internal storage. Plus, as with smart phones, such devices seem to be intended to be disposable, having batteries that may not be easy to replace.

For now, I've decided to re-use an old Android Moto smart phone with a MicroSD slot, with support for up to 512 GB of storage. I wasn't overly-optimistic at first that this would work after so many years. In fact, two other candidate phones couldn't be started. However, as I began to charge this one, it started OK and the battery seems OK. I've removed or disabled as many apps as I can, disabled wi-fi and bluetooth and as there's no  sensitive information any more, I've removed the screen lock, leaving what is in effect just an mp3 player. The google search prompt won't budge, but it's not a big deal. For now, it has just a 4 GB card in it and it's being used to play a mix of mp3, wav and flac format files. I'm planning to replace the card with a much larger one - how well it scales up in practice, we shall see.