Levin Guitars were own by C.F. Martin at the time this advert for Levin acoustic guitars was published in July 1974:

The Sound of Wood. A Levin guitar is pure all the way—precious wood all through. Take the guitar top, for instance. It's made of alpine spruce. From trees three hundred to six hundred years old. They grow extremely slowly. Imagine what that means. Wood with close grain texture. Precious wood. Have a good look at all the parts of a Levin guitar, all assembled perfectly by hand. We use much the same type of tools as used by the individual guitar maker. As used by the artisan of old. For making a guitar is a work of art. And it takes time to make a Levin. Six months, and that’s the truth, if you don’t count the centuries of the alpine spruce. To help you understand we will tell you a trade secret. There are no parallel planes in a Levin guitar. They are deliberately and expertly made asymmetrical in order to create the best acoustical effects. You'll find this same refinement in the world’s concert halls. A fine idea which we adapted. Levin guitars cost a bit more than plywood ones, but far, - far less than the ones made by the artisan working all on his own. And still you get the sound of wood. THE SPECIAL SOUND OF LEVIN. A.B. Herman Carlson Levin - The C.F. Martin Organisation