Can you make an output and input?

[GREENMACHINE]

Hey guys,
Im bored and was looking for something to do and I found an old stereo system CD player thing we had in the garage and I have some decent 5x9 speakers, I want to swap the speakers in the old CD player with these speakers (which isn't a problem) but the CD player only has a headphone output built into it, is it possible to convert the headphone output into an aux or a guitar lead size input? Its just so I can use it for playing my mp3 player or even a bass guitar or something through, but itl mainly be for music and mp3's

Thanks for your help,
Cav

[Ch0jin]

The short answer is no, you can't turn an output into an input.
(Said the actress to the bishop)

The long answer is yes, you could achieve the desired end result, but there's a bit of messing about required.

Ideally the stereo would have had some kind of AUX input. If it had, you'd plug your MP3 player in there. If it did have the AUX input you'd still need a preamp for your guitar or bass though.

If you -really- want to do this, here's the surgery involved.

Firstly you need some kind of preamp for your guitar. You could use something like a pocket POD that has a headphone out jack or you could build one as a kit. You need to convert that guitar signal into a line level signal.

You'll need to strip the unit and locate where the line level audio from the CD player enters the amplifier section. Depending on the volume circuit you may be able to go in before the volume control and therefore retain it's functionality, or you may have to bypass it. Either way, once you've tracked that down you need to insert the output of the guitar preamp in here. I'd run some stereo shielded cable from that point on the PCB to a couple of RCA's on the back of the stereo somewhere and then plug your preamp into that.

If that sounds too complicated, then it likely is.

I spent a large portion of my youth performing hacks just like this, so whilst I know it's possible, I also think for guitar use it's a massive waste of time.

Your guitar is going to sound like *** through this setup, and forget about your bass. Honestly, the cheapest nastiest guitar amp is going to be more fun to play through than a hacked boom box.