Hello, I registered specifically to provide you with this information. I am John Klingberg's daughter, however, my parents were seperated when I was quite young and I did not know him. I figured I'd have time to get to know him as I got older but sadly he died at the age of 39 in 1985 and so we never actually met, aside from when I was a small child.
He live in various places, spent much time living around Woodstock, NY. Two years before he died, he and his girlfriend moved to Oklahoma. He did play many instruments so it makes sense that you recall him playing the trumpet. It sounds like you knew my dad in NYC, it's quite likely. However there was another John (Plantania) who also played on Moondance.
I have some information from a writer researching some of Van Morrison's band members, Brian Toscano. Early in his music career my father played with Dario And The Rainbows (later called Dario's Inferno) and with an R&B cover band called Randy and the Soul Survivors. Apparently he was playing trumpet at the time, though the publicity photo I have of the two bands shows him holding a bass. These bands never recorded an album or track, as far as I know. He did the two albums with Van Morrison, Moondance and His Band and the Street Choir. Shortly thereafter he played on a Martha Velez album called Hypnotized. He is also credited on some of the outtakes of the Van Morrison compilation album Philosopher's Stone.
As I mentioned, I did not know my father but thought I'd share the information I have regarding his recordings. There are only the four that I mentioned above, the Martha Velez album and the three by Van Morrison. I hope this is helpful. It's nice to see that my father is remembered as a musician after all these years. I'm sure he would have been pleased to know that.