Update..... The Dr Z Maz18 Jr I got a couple of weeks ago developed a "sympathetic" buzz. On Monday, I took it back to the shop where I got it and they took it to bits and checked / tightened everything up. That has reduced the buzz significantly but it's still there on a limited range of notes / frequencies. It's going back again this coming weekend and I'm hoping they can resolve it fully. Otherwise, I'll be looking to swap it for similar. Far from the end of the world, but why is life always so complicated....?