I just purchased a Zoom B3 from Amazon. It's a good and versatile. However I noticed some noise problems, especially for preset patches. I'm not sure if it's a defect and should I return it. If you also own a B3, could you tell me if this also happens on yours? My steps to test it is: Factory reset Zoom B3. All patches are default. I'm using the Zoom adapter, so I think the power supply shouldn't be a problem. Signal chain: Active bass -> Zoom B3 -> Fender Rumble 25 amp. With Patch A1, Turn all effects off in B3. Adjust the amp to get reasonable volume for normal fingering play. (9 o'clock on Fender Rumble 25) Switch to other patches default. I found it's pretty noisy on some of the patches, like J9, J0, I8, I6, G3, D6. It's very noticeable with the same volume setting. The most weird thing is, the noise still exist even if I turn the volume off on the bass, or unplug the bass (so there is nothing in the input jack)! It's really weird that the noise still exist when the instrument is unplugged (so there should be no input signal). I also noticed that the output level may be very different between the preset patches. Is this problem just an output level issue? It's a bit disappointing, because ideally I'd hope that the preset patches can have similar output level, so new user can easily switch between the presets.