TromboneChat

I have a Conn trombone that I want to properly identify. I believe it is a Conn 10 (see stamp in photo). The serial no. is 349XXX which I place at 1942-43. I'm a little confused by the bell size which I measure as 7" rim edge to rim edge.

I have attached some photos. Do I have it right?

10 doesn't seem to be right for a model number - Conn's usually have a model number that is a combination of a number followed by the letter "H" which is the designation for a slide trombone. See if there's a number at the top of the outer slide, or on the bell where the slide attaches (the slide receiver). That is where the model number usually appears. Looks like a 4H to me, but could be a 24H, or maybe even another model that is more rarely seen.

Jim Scott

Thinking 24H because it's bell tuning and has the additional support on the cork barrel brace.
https://cderksen.home.xs4all.nl/Conn24H1940image.html

It's not a 10h. 10h is 8" Coprion bell. It is a pro horn though based on all the nickel silver. Could be 24h, 4h, or even a 30h. A lot of models had a lot of bell size options. 24h hand slide brace does give it away, though. 24h are great horns, but don't sell for a lot. Look for the model # on the bell side connection. Or on the portion of the hand slide that gets hidden in the cork barrel.

the handbrace gives it up as a 22h or 24h. both share engravings and brace and everything just really different bores from what I remember. where you see the serial number look down to the outer slide and the model number should be there maybe on the part that is hidden under the cork barrel end when fully sheathed. also should be on the tenon receiver on the bell side.

the 10 is just like an internal batching/pairing number conn used when manufacturing parts to make sure batches kind of stay together. if you look down from that 10 and pull the outer slide a bit so you can see the end of it, you'll probably see the same number on the outer slide. indicating that those inners/braces and the outer were paired. this probably done so they know which ones went together after they got treated for like lacquer or final cleaning or whatever where multiple horns were all being done at the same time

at least for a long period, for conns you can find serials on the tenon side of the brace and then model number and serials on the outer slide right below that. model number would also be visible on the receiver usually. and then on the mp receiver side you should get matching numbers on the brace and outer slide right below that.

That’s a 24h. Ballroom version of the 4h (set back bell for plunger work). I have one the built the same year. Small bores don’t get any better than that.

You guys were spot on! I just needed to pull the slide out a bit. It sounds like a good horn and if it's like saxophones, a good vintage for Conns. I had a friend try it ( a pro trombonist) and he said it played really well. He took it home and took a long time to bring it back

Is it a good horn to learn on? I've played sax most of my life but always wanted to play trombone. The Dorsey Bros did a number on me.

slidehamptons wrote: Mon Dec 08, 2025 9:38 am ...
Is it a good horn to learn on?

It's a great horn to play. The upper range is easy. It gets a lot of sound for such a small bore. It doesn't take a lot of air. You'll be kind of spoiled because there will not be many horns you'll be able to go to to get a cheap high range improvement. Maybe get the slide worked on, but it looks ready to go. I can't really suggest a good beginner mouthpiece for this, but if I were just playing it, I'd get a Doug Elliot probably C cup, in whatever range to fit your face.

elkhart era trombones are well known for being quite nice. I have a silverplated 24h myself and it's a really fun horn to play. I'd say yes it's a good horn to learn on. and there's not much you'd be able to upgrade to from it if you are wanting it. it's a vintage horn with that Conn sound people talk about so you'll never really "upgrade" unless you are just searching for a different sound that isn't quite what this produces.

and those pictures of the 57 markings are just another version of what I had mentioned in above post. It's to keep the tuning slide and the rest of the bell section paired during assembly so that they are identifiably a pair as they go through various finalprocesses that requires them to not be assembled. Reason being, the tuning slide and bell section are aligned to each other and will not necessarily fit properly or be aligned when fitted to another bell section or tuning slide. that also is the case with the hand slide outers and inners. they are aligned to each other and may not align well when you try to swap with another.

Thank you for the great observations and advice.