Interesting thread. I recently purchased a 70s Series I and my first impression was that it sounded more open when compared to my 2005 Orion, which I felt had a deeper, richer, and/or smoother tone. I'm using Pyramid Gold flat wounds on both basses. From what I understand, the Series I had pickup upgrades sometime in the 80s. Although, I guess there are a variety of factors that could contribute to this apparent sound difference, including wood combinations.