Open vs closed

[foxhunter]

I have read about theoretical differences in open vs closed. I am looking at a couple of older Bach 42's online. One open design and one closed. The only two horns with f attachment I have played are kings with closed design. Can you really tell a difference in how they play?

[BGuttman]

Some people claim they can. I find that the size of the valve openings is more important than whether it's a closed or open wrap. I never found the Bach Stuffiness on any King or Conn I owned.

[opinion] Opening the wrap on a Bach 42B without changing the valve makes little difference. Going from a Bach rotor to an open valve like an Axial, Hagmann, Meinschmitt, etc. makes a big difference. Note that many of these valves REQUIRE an open wrap simply because of how they are built. [/opinion]

[Macbone1]

I agree with Bruce - the biggest difference is made in the valve, not the tube wrap.
Some tech shops will bore out conventional rotary valves to round out or "lap" the ports better than the factory does. I had one done at Osmun and what a nice difference in both open and closed response. (It was a German make). I suspect any basic rotary valve Bach or Conn is a candidate, for ex., but some models won't have enough metal to spare inside the valve.

[tbonesullivan]

I agree with Bruce - the biggest difference is made in the valve, not the tube wrap.
Some tech shops will bore out conventional rotary valves to round out or "lap" the ports better than the factory does. I had one done at Osmun and what a nice difference in both open and closed response. (It was a German make). I suspect any basic rotary valve Bach or Conn is a candidate, for ex., but some models won't have enough metal to spare inside the valve.

I have rarely heard of people complaining about stuffy Conn trombones, even the older elkhart examples. The problem isn't just the valve on the 42, it also is the gooseneck, which I think is the same one used on the 36. The valve is undersized, the ports are undersized and not machined well on the Bachs. Current Conn trombones use a different valve, which is not undersized, and the rotor ports and knuckles are a much better design. Just LOOKING at the them you can see how much better the approach to the valves are.

If you are looking for a 42,I would recommend the 42 BOF, which has a better rotor, better wrap, and better bracing.

[foxhunter]

Learned a lot here. Thanks guys