My amp has an 1/8" headphone out jack, and messing around one day, I found that if I run that into the aux input of my stereo system, it gives me distortion like the Beatles' Revolution. I'd like to mess around with it more but I'm worried it could mess up my stereo speakers because they're not exactly meant to be used as a guitar amp, and they're only like 7 inch speakers. Should I worry about it, or can I keep doing this without worrying about anything bad happening?
Well, the aux input of your stereo system is meant for line level signals. Line levels signals are fairly low level - higher ouput than from the pickup of a guitar, but much lower than the output from a headphone jack. The other thing is, the impedance difference between a headphone output and an aux input are quite a lot. The headphone output is probably somewhere between 8 ohms and 150, or so. The aux input is likely around 10k ohms. This will effect the tone

What you're doing is overdriving the first stage preamp of the aux input, so it clips - creating distortion. So, can you do it without damaging anything? Yes, if you're careful. Don't crank the headphone volume too loud, or you risk burning up the first stage preamp. Bring it up high enough until it distorts and no more. As long as you do that, feel free to experiment away. That's how new things are discovered.

Edit: Also, don't turn up your speakers super loud. Keep the volume reasonable and you'll be fine.
Last edited by KG6_Steven at Apr 1, 2011,
That's kind of what I was thinking, but I couldn't find anything, thanks a lot. I'll keep it up then!