TromboneChat

I have a nice 70h and really enjoy playing it, but don't really know when I will be able to play it outside my practice space.

I might be considering adding a second valve to increase the likelihood of using it in a bigband or ensemble.

My goal would be to keep it as close to the original as possible, so I would appreciate your inputs, ideas, pictures etc. on how to best integrate a modular/plug-in second (dependent) second valve.
Pictures would be really fantastic!

Some thoughts and questions from my end:
- I would want to change as little as possible on the instrument. What would be the best way to realize the second valve trigger/valve lever (for the middle finger)?
- How would you shape and place the valve tubing (for a second valve in D) so that it doesn't get in the way?
- I understand the plug-in valve would basically replace the current valve tuning slide. That slide is pretty narrow. What actual valve would be the best choice? In my expectation best would be a rotary valve that is pretty open, but has a relatively narrow casing to fit into that space

Any totally different inputs?

Looking forward to your ideas!

I also have a 70H that I want to be more useful (and perhaps more importantly, more balanced).

A neat fact: the 70H J bend only expands by .10 in the space it would take to put two modern rotors.

Since my '55 isn't a pristine example, it's getting chopped up and getting two independent rotors for sure.

I have seen your video already, liked it as always! I would definitely stay with a dependent setup and this time prefer a modular option.

A plug-in is the way to go!!!! Luckily Conn tubing is on the larger size for bass tubing so matching a valve up with the tubing diameter would be easy. Maybe a vintage Conn valve would be best if you can find one.Someone was selling a Conn 72H with a plug-in valve somewhere-

I made a slot in for a friend's 71H which worked very well. For reasons too lengthy for here, he no longer needed it, so I bought it back. It would be nice on my 70H, but when I checked, the 70H valve tube is a fraction smaller. You will need to get the valve made as a custom fit, as tube size changed over time.

Good to know! would you be willing to share some pictures of how it is built?

Sure. Will do tomorrow.

Here’s a few pics from my library. I’m not sure where they’re from, but probably Horn Guys or Brass Ark.

Ken, that is a Kanstul slot-in. Very nice.
Here are a couple of pics of my slot-in. It's very dirty looking as it's been in storage.

Funky reversed tuning slides Chris!

It's not like a typical slot in, it's all to one side. No reverse tuning slides.

It was built for a 71H, so the extra tubes run down the middle of the bell section. The original valve tuning slide completes the set up.

Similar to one I made for Max Seigel
The only issue with the drop in valve may be the amount of clearance from the main tuning slide/bell branch. Not a huge issue, but takes a.little bit of reconfiguration, and potentially one new part on an existing instrument

Burgerbob wrote: Mon Oct 20, 2025 12:59 pm It's not like a typical slot in, it's all to one side. No reverse tuning slides.

Doh. I see it now!

Chris and Matt, those look awesome.

Thanks everyone and sorry for not coming back earlier (vacation...).

The one thing that I really don't like is the very long and exposed linkage that is obviously required.
The way Matt has done it looks somewhat "protected" and least in the way of the shoulder.

It's not urgent to get this done, but this is some good inspiration.

blast wrote: Mon Oct 20, 2025 6:33 am Ken, that is a Kanstul slot-in. Very nice.
Here are a couple of pics of my slot-in. It's very dirty looking as it's been in storage. 20251020_132907.jpg20251020_132928.jpg

That looks very much like the drop in valve Terry Pierce built for my 169.
I wish I knew how to share pics on this site.
This is a cool thread.
Noah has a 72H w a drop in valve on his site too, for what it’s worth…

Also keep in consideration that finding a case/gig bag for a slot in is difficult. You're stuck basically with gig bags only if a certain type.

bassboneman69 wrote: Thu Oct 23, 2025 2:02 pm

blast wrote: Mon Oct 20, 2025 6:33 am Ken, that is a Kanstul slot-in. Very nice.
Here are a couple of pics of my slot-in. It's very dirty looking as it's been in storage. 20251020_132907.jpg20251020_132928.jpg

That looks very much like the drop in valve Terry Pierce built for my 169.
I wish I knew how to share pics on this site.
This is a cool thread.
Noah has a 72H w a drop in valve on his site too, for what it’s worth…

I can load pics onto this site from my computer. Can’t you?

Thanks again all for the thoughts and advice!

Alternative idea:
What do you guys think of instead of adding a second valve, adding a second trigger to "remote extend" the valve tuning to E? Kind of like a Thein Bartok valve.
This video shows a seemingly nice way to realize it:
Interestingly the shop that did that conversion is just a few kilometers away from me.
I would however keep the valve lever on the thumb and put that "valve extension" on the middle finger, not as it is done in this video.

What I find intriguing about this alternative as compared to adding a complete valve:
It's even less intrusive to the instrument, adds less weight and I assume has potentially even less impact on how the instrument plays. I mean, it simply does not add a second valve...
It would still be relatively close in the playing logics to using valves in a dependent system, just that it only has the E, not the D. Obviously that needs getting used to, but it's much more than just having the F valve.
I assume this would be a bit cheaper to build as the parts are pretty basic/no valve. It may require more testing and trial, but that shop has done it before, so it should be fine.

Has any of you thought about or even done the same?
To the techs: What do you think could be problematic?
Things that come to my mind:
- Getting the valve tuning slide loose enough that it is easy to operate.
- Building the mechanism in a way that it is at the same time stable (it requires quite some leverage), but also still fast enough
- Building it in a way that is protected as much as possible/not sticking out too much with all those parts

MStarke wrote: Wed Oct 29, 2025 5:32 pm I would however keep the valve lever on the thumb and put that "valve extension" on the middle finger, not as it is done in this video.

My guess is that one wouldn't have enough physical leverage to make that throw with a middle finger paddle feasible.

Thein make one with Hagmann valve which uses the middle finger for the slide throw activation

I also don't really see why this should be an issue with the middle finger. If the in does ist it will probably work.

Burgerbob wrote: Thu Oct 23, 2025 4:13 pm Also keep in consideration that finding a case/gig bag for a slot in is difficult. You're stuck basically with gig bags only if a certain type.

My 72H with a similar slot-in the Chris's (Blast), fits in a ProTech case quite well, including the longer hand slide. Unfortunately, it's not that light a case.

Those Thein "Bartok" single valves with the crazy multiple leverage points in the contraption that throws out the tuning slide to flat E are cool, but I have always thought that if something goes wrong, somebody is losing an eye!

Jim Scott

Burgerbob wrote: Thu Oct 23, 2025 4:13 pm Also keep in consideration that finding a case/gig bag for a slot in is difficult. You're stuck basically with gig bags only if a certain type.

Sadly, removing plug in valve is the only way I can (safely) carry trombone ina gig bag.