I attempted a true bypass modification myself and failed... The exterior has many scratches and is in poor condition. I was able to confirm operation with an AC adapter. I have not tested it with batteries. I confirmed that the bypass sound and the sound when the effect is on are produced, but the sound disappears for about 0.5 seconds when switching on and off. Also, I cannot confirm the sound output from OUT-2 in Stereo mode. One of the screws on the back cover has been replaced with a different one. This is a junk item, so please refrain from purchasing if you are sensitive to such things.