hi. i have some oscillating toy sound circuits built. I want to plug them into my amp. Some of them use the lm3909 chip. I don't know where I got the LM3909's, but they're hard to find and expensive, so I'm also using some 555 timers. the lm3909 seems ok to plug straight into the amp, though could use some help. The 555 gets fried when I do. What do I need to place in between the amp and the toy circuit to protect the amp, and help the sound out a little? I'm not so concerned with modifying the sound a little, I'd prefer simple to accurate. Is an op amp the way to go? I have an LM358. Is this the same thing as a pre amp? Any help is greatly appreciated. OH! or could I even just put some transistors in between the amp and the circuit? or would this seriously effect the sound?