String Buzz Octave Mandoline

[BlackGrass]

Hey there, I just bought an Octave Mandoline Standard (made in Portugal) from german instruments supplyer Thomann (I do live in Germany) and I`m facing a stringsbuzz issue on the G-strings...The buzz happen when playing them open. It`s my first OM but I`m familiar with regular bluegrass or italian bowlback mandos. Few facts I can already tell: Fretboard has a zero-fret but the nut is defenetly lower than the zero-fret. The neck it`s absolutely straight, even too straight I guess, but loosing the truss rod (single one) make that buzzing even worse.
I can`t find no loose screw anywhere, neither strings parts touching somewhere...Tailpiece is not the problem...The buzz actually occures when I play chords with open G strings and only when I hit them powerfully...as if the two strings are touching each other while oscillating and maybe the issue has nothing to do with necks curvature...Does anybody have any similar issue or suggestions about ? Thanks in advance for any help or suggestion!

[pops1]

I have found the truss rod to be the source of the buzz when playing certain notes. It was loose in the channel and I had to remove a fret around the 6th or 7th fret and put silicone in a hole drilled to the rod to keep it from vibrating. It was a pain to diagnose. It may be the G strings hitting each other, but when you said loosening the rod made it worse I would suspect the rod. Maybe tighten it a touch more and see what happens.

[MrMoe]

BlackGrass
Hi there, I find the octave mandolin to be particularly prone to buzz's and rattles. I am not fond of the zero fret. Based on your observations I would first check for a high fret, # 1 may be high. Improper bridge slots can cause a rattle, they usually show up in various spots along the scale. Improper nut slots rattle. A neck that is perfectly straight will require higher action than one with the correct bow. A noisy truss rod is a difficult fix, they also tend to act up in more than one spot. If the truss rod nut needs to be loose a drop of pine tar on the threads can help. The list goes on. Technique is also a biggy. I tend to pick with an inappropriate motion which, when done hard, makes the courses vibrate in a circle and touch. Best regards, Maurice