Headphone Amp with AUX input?

[slashandburn]

I was thinking about a simple way to marry off my belt clip headphone lm386 amps and all the backing tracks I've got stored on my phone. A quick search here brought up this, Paul's post made me realise it might be a little more straightward than I first thought.

https://www.diystompboxes.com/smfforum/index.php?topic=110733.0

> play along with some music through headphones

This means a Mixer. Mono guitar, stereo CD, knobs on each, two outputs L and R.

Follow that with some gain and power to drive headphones.



This does NOT mix CD into the guitar amp. That does not seem to your need(?). Adding that frill would need more parts, and I am too tired this week to be so clever.

The guitar input probably wants to be buffered against the mix network impedance.

"CD" may of course be WalkMan, iPod, etc.... any hot stereo line level.

As the "CD" is likely much stronger than guitar, I've used larger mix resistors on the CD side.

Pots may be 50K, and probably Audio taper.

The hi-gain output stage may be LM386 with about 180 Ohms between pins 1 and 8. Do not omit bypass cap on Pin 7. Somewhere recently I posted a detailed LM386 headphone-amp plan.

I have shown the Amp Out coming from the guitar buffer because it seemed convenient. If you are adverse to an extra buffer in your amp-chain, take amp signal before the buffer with an either/or switch. (Could be a switched jack?)

Have I just not had a enough coffee yet or is it really going to be a simple as just building a 386 headphone amp, tacking on a stereo jack socket for aux-in and running both through a shared stereo buffer on the headphone out jack just as Paul outlined in the quoted basic mixer circuit post?

Im not doubting Paul for a second, more myself and my own understanding. I think I must be missing something.

[slashandburn]

*bump*

Haven't had a chance look at this but still halfarsedley thinking about this. Looking at it again I've totally misread Paul's post. The guitar in path doesn't look like what I'd want, I'm assuming to get something functional for my intended purpose I'd want to have the "amp"  path in series with the guitar input.
i.e: guitar in> lm386 > out
Parallel to
AUX in> (no  further amplifaction since its already hot) > out
Both feeding a basic 2 channel stereo mixer circuit with independent level controls, possibly with a buffer on the Out (not even sure if the buffer would even be necessary)

Excuse my ignorance. This has probably already been done to death on here and I'm just not finding the threads. I should know this shit. I feel I should also know why this likely wouldn't work.

Am I miles off here or could I actually pull this off with a 9v battery, a guitar and a  mp3 player/iPhone loaded with backing tracks with a view for headphone playing on the fly?