Posted by Tom Mason on April 02, 2003 at 18:31:14:
In Reply to: bass bone posted by Mary Ann on April 02, 2003 at 09:47:10:
I'll try to be brief.......lol
Many of the comments already made are very good. I have not seen a discussion in depth about valve construction besides naming the models and versions of wraps.
Bass trombones are being made with basically 2 valve configurations. One is based on the traditional rotor concept like what you are familiar with on french horns or rotary valve tubas. There are a few variations on the rotor that attempt to open the air flow by either matching or expanding the opening of the rotor to air. Some good variations are the Greenhoe, Conn Lindberg valve, and the Willson rotax valve.
The other arrangement is the axial flow system. This system attempts to open the flow of air by straightening the flow of air through the valve. This is done to eliminate quick bends in the flow, and lessen resistence. Popular versions of the axial flow valves are the Thayer and Hagmann valves.
A valve set in the middle of these are the Bach balanced valve and the Miller valve. Both of these valves involve using an oversized rotor with axial flow passageways drilled into the valve. All axial and these two systems utilize open wraps. The open wrap is a system of slides and tubing that takes the least amount of bending to complete the air flow circuit. Traditional wrap systems utilize more bends in the tubing to make the area of tubing compact.
If you are looking for a horn that will give you a lot of options for a little money, I suggest a Holton TR 181. It has an independant Bb F Gb D arrangement that can be changed to Bb F G Eb by not using the 2nd valve extention. The Getzens mentioned are also good for the money horns. Both use traditional rotors, and will offer a little air resistance.
Conn makes a set of bass trombones that are also good. Currently, they are offered in traditional rotors, although I have heard that the Lindberg valve will be offered in the future.
Bach, Edwards, and Yamaha offer more expensive horns, but are usually the more popular. Bach offers traditional rotor, balanced valve, Hagmann valve, and Thayer axial flow. I have heard that the Greenhoe valve may soon be an option as well. The rotary valve horns are offered in traditional and open wraps. Yamaha currently only offers rotary valve horns in both traditional and open wraps. Edwards offers Thayer valves, and a system of interchangable leadpipes and bells.
Thein makes a very good but very expensive bass trombone. They use Hagmann valves, and have a wide variety of options. Greenhoe makes valve and bell sections as well as valve sections. I believe that at one time they were going to make complete instruments, but I am not sure at this point.
There are places, such as som eof the places listed in earlier posts that will construct a bass trombone for you. You would have many options of valves and slide combinations, but will pay a high price for your instrument.
I personally use a Bach 50K3. It is a double in-line independant bass trombone with 2 balanced valves. It has the axial flow without the need to disassemble the entire bell section to clean the valves.
sorry this is so long.
Tom Mason