Help! Telemann and two clarinets?! In a concerto? Does this make sense?

Question

About 15 years ago, I found a cassette tape (with no case or jacket) in one of my parents' old boxes of junk that was simply labeled "Telemann Duets." It was obviously professionally made, and the sound quality was good. On it was a large assortment of two of the same instruments (duets) playing WITH ORCHESTRA. So, concertos? Double concertos? Whatever the term is...
One of the concertos was two clarinets. It was very appealing, not too virtuostic. The first clarinet stated the theme, and then the second one came in and played in harmony with the first. They were not canonic.
Anyway, I played that tape over and over for maybe a year until it literally fell apart. The tape's... well, tape, got stuck on some part of my player and I had to break it to get it out. But the theme still plays in my head! After all these years I can hear it clearly.
I realize this might not have been written originally for clarinet. I've searched and listened to many, many file sharing site

and none seem to have the same combination. I have also tried a lot of "other" duet pairs- oboes, flutes, recorders, etc.
Has anyone heard a Telemann concerto with clarinets? (and yes, I know it was clarinets, I was playing one in wind ensemble at the time) or know where there's a place I can find such a thing?

Answer 1

Since the clarinet was not invented until the late 1700s
( Mozart's clarinet concerto was the first written for the instrument), your piece was a transcription. I'd look for works for oboes or flutes instead. Check out the Wikipedia for some easy research, and they may give you other leads. Otherwise, go to your local university's music library and find a biography with a list of works ( Werkverzeichnis in German) to see if anything fits.
Happy hunting

Answer 2

It's called the Concerto for Two Chalumeau and Orchestra. The chalumeau was sort of the predecessor to the clarinet.