Tracking down a buzz/vibration

[Sandstorm]

Greetings,

I have a new to me Epiphone IBGC 1957 SJ-200 in antique natural.  Got it pre-owned at a very reasonable price and for me, it scratches that fancy jumbo/maple itch I've had without the significant cash outlay of it's Gibson counterpart.

As I strum away on it, I really dig the sound and feel of it.  Picking notes are all clear, set-up is great...

My only gripe and I'm hoping for some guidance on...I've got a metallic sounding buzz that sounds like it's coming from the bridge area.  I notice it mostly on G, D and sometimes A strings, particularly when I play on the 2nd -3rd fret with a thumb rest stroke.  I notice it on the low E and A strings sometimes around 5-7 frets.

-To provide a few extra details, I've removed the guitar electronics (LR Baggs VTC under saddle) and installed a new saddle...and even when using the old saddle, the sound still presents itself.

-I've bought new bone bridge pins and fitted them snug to the bridge.  I had a second unused set of Graph Tech pins I've also swapped without it fixing the problem.

-I've added neck relief so the measurement is approx 0.25mm at 7th fret (with first fret pressed and 15th fret pressed.  I've tried adding more relief but it didn't fix the problem and just made playing the upper register more difficult.

-Action at 12th fret is 3mm and 2.5mm respectively on low E and high E

-All the tuner screws, truss rod cover screws, strap buttons are tightened.  As the guitar has no electronics, I don't even have an end pin in it now so definitely no buzz from there.

-I've run 13-56 and 12-53 gauge strings and made no appreciable improvement.

-I used a string action gauge ruler to rock the frets and there's no rocking or any real visible low spots.

-There's no buzzing on open strings so I don't think it could be a nut cut too low.

-If I play the 2nd fret note right at the fret, it is basically gone, however, there are some chords/arpeggios where if you are playing an Am chord in 1st position where physically, your 2nd finger cannot play right against the fret but more in the middle.  When I play my other acoustics, I don't get such noise so really it is something isolated to this guitar specifically and not a technique issue.  I've had it for a couple of months and I did see it before I bought it, and I didn't notice anything upon initial playing because I didn't play every note on every fret intently listening for buzzes, and if I did, I might have thought it would be something a new set of strings and set-up might take care of.

I'm kind of at my wits end because as a finicky guitar player, once I find a buzz, rattle or vibration, I can't unhear it and just keep playing it over and over and tinkering to drive myself nuts.

I do get a free set up from the music retailer that I bought it from, but these types of things I just found most shops just change the strings, play a couple chords and say it's ready for pick-up.  No one is really going to take the time someone would spend working on their own instrument.  On a separate note, I do find most people use the term guitar tech and luthier interchangeably, but it's my understanding a luthier actually builds guitars and there's no "luthiers" in my area.

I feel all things considered it sounds like it's coming from the ball end/bridge plate area and even really pulling the strings up to lock against the bridge plate I still have that issue so I dunno.  Taking a photo of the bridge plate area didn't really reveal anything to me out of place.  My last idea was to get from amazon a brass plate with holes drilled for the bridge pins that I can plate on the bridge plate so the ball ends have a hard surface to make contact with.  Problem with this is that I intend to install a K&K pure mini and that combination won't work.

Hoping to draw on some of the forum's experience to solve this, it can't be an unfixable issue.

[B0WIE]

 You gave great info, so sorry if you covered any of this (which I'm sure it does). But, I can best diagnose by starting with a few questions.
-Can you isolate it to one note or a couple of neighboring notes? These notes would cause a buzz regardless of the string.
-If it's not a particular note, it's usually either a single string or it's a place on the neck (specific frets).

There are so many places a buzz can come from but I've discovered nearly all of them. We just have to go through the process of elimination.

[Sandstorm]

You gave great info, so sorry if you covered any of this (which I'm sure it does). But, I can best diagnose by starting with a few questions.
-Can you isolate it to one note or a couple of neighboring notes? These notes would cause a buzz regardless of the string.
-If it's not a particular note, it's usually either a single string or it's a place on the neck (specific frets).

There are so many places a buzz can come from but I've discovered nearly all of them. We just have to go through the process of elimination.

It seems to be around the 1st to 3rd frets but can get it around B notes most easily. 

It may well be a loosened ball end for one string that gets excited by certain notes or is it possible a low nut can cause buzz on low fretted notes?