I also have a 1970s 71H, but have not seen a lot of comment about these horns on this site or TTF. I find mine a little stuffy in the low C and D region (with trigger), and I'm wondering whether it is the horn or my chops. Otherwise, I also love the sound from the horn.

My alto sax-playing father just mentioned a Parduba double cup mpc for trombone to me that I had never heard of before. I'm intrigued, but is it a gimmick, a fad, or something worth looking into? It does not show up in my Picket mouthpiece comparability app, so I'm wondering how their sizing compares?

Also Michael Davis' Hip-Bone Music Videos of interviews with various brass players, and the New Trombone Collective videos.

There are 10 copies for sale on Discogs.com

In Firefox, I over-rode the security issue once, and it has not come up again.