[SpookyZalost]

Very good guide!! My brother did something very similar. He wired up the entire amp unit and used some custom electronics as you described. It ended up working very well.

I like how you're creative about using a computer power supply. Hey, I mean, sometimes the solution is right there. This is one of those situations it seems.

Do you use custom speakers generally as well, or use the ones included in the car itself? I find that with a good sound system, the stock speakers can sound quite good. But they do get worn over time. Most of my older cars had problems once the volume got turned up a little higher.

@darth: the nice thing about car speakers and old school speakers is that they work the same... to the point that you can take some OG sony speakers from the 70's/80's/90's, and wire them into your car, the stereo unit it's self is a decent driver.

just wire the grounds and power leads (red and black wires), appropriately... or if you're really up for it, get a terminal block so you can hook up some speakers without needing any extra work.

you can also throw a secondary amp in if you want to, it's just a voltage regulator, and a potentiometer to adjust the voltage.

Voltage = Volume

Looking forward to see what you come up with!
If the total cost minus labour ends up being considerably cheaper than a stereo then I might just consider making one myself as well. As nice as bluetooth speakers are, I've got tons of CDs and tapes that I'd like to play that I don't have on my phone.

IDK about cost minus labor but if you go with mostly recycled parts I don't see why it wouldn't be cheap, the head unit that it all goes through is like $30, old CD rom drives in the $5 range, raspberry pi or arduino, maybe $10 to $15, the most expensive part is likely the power supply and the case lol.

bonus points if you can borrow time at a 3D printer from your local library (one of the awesome things we have hear but I've heard of it elsewhere), to make custom knobs and things