Okay. I'm no electrician, but that's why I'm posting. I've been working on modding an electronic keyboard for some friends. Its a really simple little thing, basically a stylophone in a keyboard case, runs off of 4x AA batteries. Like a child's toy keyboard, really. Ive cracked it open for them and added a socket for a 6.5mm jack so they can amp it up or run it through an effects pedal. The problem I had when doing this, is, because the circuit is opened and closed with each key press, the amp crackles at the beginning of each note (this is resolved if one holds down the lowest key in the circuit and plays higher ones) So I figured that, to fix this issue, I could add a "virtual" key at the very end, with a strong resistor, so a note is "always" playing, just too low frequency to hear. Presuming this fixes the problem, a new issue arises. The thing conserves its battery energy by only having the circuit closed on key presses. Removing this feature would presumably mean more energy consumption. So to fix this, I though it would be good to add another switch, and a socket, to toggle between a 240v adapter, and battery power, a "portable mode" and "performance mode." (yes, they do use it on stage) Now the big question is, Would simply hooking up a 6v transformer for the thing work? I don't want to just go hacking away at it because im not sure the significance of current in this situation. Any advice on what kind of adapters to use would be great.