Bass Trumpet

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Ahh, the bass trumpet... should be a valve trombone, but should be a large trumpet an octave lower than the standard C/Bb trumpet that everyone seems to start out on in grade school. The name sounds cool, just as all bass and contrabass instruments are, yet it seems to be just a valve trombone with smaller bell.

I found a CG Conn bugle in the key of G/F (the main tuning slide allows for enough pull to drop the pitch to F and then be able to tune the bugle in F as well (there's a little line to show where F is)) and while I considered having some sort of contra-alto or contrabass trumpet in G/F, it seemed more appropriate to have it in tenor range like a trombone - lot's of trial and error here, I'll explain:

I took a trombone bell from the scrapheap and burnished all the dents and deformities out as possible, soldered it on to a trumpet tail crook, and then attached it all to a King 600 trumpet block. Strangely enough, this dropped the pitch to Ab from Bb. It worked and had enough pull in the valve slides to play in Ab, but I wasn't real happy learning a new fingering set or transposing. So I went back to the bass bugle (something like 12-13 feet) and cut one of the tubes in half and placed the King 600 valve block into it.... BAD IDEA!

It played awful! The leadpipe and tuning slide made up the first 6 feet or so of .48x" bore then dropped to a .46x" for about 4 inches then back to the .48x". Very stuffy, very unhappy.

Scrounging for a .480" section was impossible, so I decided to cut down the total length. To bring it from G/F to Bb (in the tenor range), I needed to remove 4 or 5 feet - easy enough, it's all cylindrical bore tubing before the bell tail. So removing most of the tubing, without drastically cutting anything as it may not work, I came down to a trumpet pitched in flat C, not Cb (C flat), but a C that was flat. Great! Knowing some C tuba fingerings, Bb had to be first valve.

Not in this case. Since the valve section is still in trumpet Bb, all the tuning slides mean SQUAT. After a bit of playing with different fingerings, I figure out that 1-2 or 3 would give me Bb - granted it was a stuffy Bb because of the small loop of small bore tubing, but I was at least heading in the right direction. The main issue was placing the MAIN tuning slide.

I couldn't place the main slide where a normal trumpet slide is, otherwise it would run into the bell or not have enough pull to tune it in all types of weather. So looking at the parts I had in front of me, I removed the tuning slide from the leadpipe and measure from the tail to the valves. Asking a few trumpet and horn players about tuning helped figure out that about 3-4 inches were needed, just about what I had for clearance in that area.

Not knowing exactly how much I needed for bass Bb, I taped down the third valve and pulled the slide out to where Bb should be. A little tuning hear, a little organ drone there, I came up with about the proper length I needed for the main tuning slide. The original tuning slide was about 13 inches long on each end, so I need to take off about 5 or so inches from each tube, well one side is a little longer than the other to make up for the placement of the valves.

At the moment I have things tacked on just enough for me to play it. It looks like a long trumpet - slightly larger bell and an obviously larger mouthpiece, but to me it sound like a dark trumpet, almost a trombone. The bell is, if my memory serves me, 7 inches maybe 6.5 inches wide. It's like a trombone bell that had the rim cut back, kind of like when people modify modern trombones to resemble the sackbut. The taper of the bell and throat is similar to the sackbut second from the left in this video.

I think that's what I've made - a valve sackbut. Which might be where the bass trumpet really is, somewhere between the trombone and the trumpet, not quite a valve trombone, but not really marching variation of the trombone/baritone.

Here's what I have left:

• Find longer tuning slides from the scrap trumpets, even if that means putting a slide within a slide
• Fix the clanking valves that are bottoming out on the casings (regulation)
• Cut the tuning slide and solder it into place, check tuning and adjust pitch, then repeat this until I find the bass Bb
• Tape up some braces for placement or tack them on
• Unsolder everything, clean, buff, then solder it all back together

If given the time and training, I would modify the leadpipe to give me a more even transition into the valve section. Or better yet find a .480" valve block and splice that in. I'm thinking the leadpipe might be the bad bit, it uses a small trombone receiver, so there is a bit of a bore jump. If I could locate the parts for an alto horn or an actual bass trumpet leadpipe, that would be great. For a project though, and something I could maybe play in the community band or at least loan out, it'll have to do. The mouthpiece I'm using is the one that was stuck in the bugle, it works better than my baritone/trombone testing mouthpiece - which is great for those instruments, but give me a bit too much of a trombone sound, when I'm looking for something a little darker yet with that bright trumpet sound.