Gggggas
Less about the tube type, and more about the manufacture and sound you’re looking for to choose between the 6V6 model tubes.
The “G” is the shoulder tube large coke bottle shape.
The GT, GTA, and GTY are all the smaller straight sided tubes.
Some think there is sound difference between the straight sided and shouldered tubes. This might be more personal opinion.
I tend to look for and use the older G tubes just because I like the way they look.
But I do own several of the straight sided tubes from the same
Manufacturer. For the Mazdas I own they are very similar in sound G shape to GTY shape.
The military tubes are either marked as JAN (joint army navy for US military) or CV509 ( European military) or similar labeling as it is country specific, and can be any of the G, GT, GTA or GTY shapes.
Or perhaps you may be thinking about the Bendix 5992 or Bendix Eclipse-Pioneer 6V6 which are both a GTY shape tubes.
Hope this info helps.
