Lyre mounts seem simple... But Yamaha doesn't seem to agree with us on that.
Marching instruments are designed to boldly go where no instruments have ever gone before- or at least, to go there more stylishly and comfortably. So, they have a few neat features!
Say, you're performing a piece only once and it's not memorized- or it needs to be played perfectly and so you're not allowed to play it from memory (sigh). You need some way to hold your sheet music- and normally that's a role filled by a music stand. But on a field, parade route, or in a stadium, carrying one of them around is awful. So, we mount our music to our instruments!
We clip the music to our instrument using a lyre, shown below (click image to view higher quality version of the image).

Image is compressed to save data- click here to see high quality version
It's just a clamp that holds onto a bent stick of nickel-plated brass.... How hard can that be?
Left panel shows an overview, top right shows the clamp itself, and the bottom right provides a different angle.
Photos taken by me on a Nikon D7200 with a vintage Nikkor 55mm macro lens at f/5.6, 1/50th, & ISO 2500.
So, we have basically 3 components:
- The lyre mount, made up of
- The clamp body soldered to the instrument tubing
- The captive screw that is used to lock a lyre into place
- The lyre, made up of
- A piece of bent brass square rod
- A clip to hold onto the flip folder
- The flip folder
Isn't that pretty simple? Well no, it's not. Allow me to explain:
Angled Geometry
Part of the point of a lyre is that it holds the music at a convenient playing position- and so, the lyre must also hold it at a convenient angle. The music shouldn't be tilted off into space so you can hardly read it. This sounds simple- just put the lyre mount at a 90 degree angle and it's not an issue. But, Yamaha, in their infinite wisdom, decided to put their lyre mount at an angle. So now their lyre is substantially more complex to compensate. For reference, here's an image of the YAC-1508N lyre:

Image is compressed to save data- click here to see high quality version
The N in YAC-1508N signifies that this is the nickel plated version for use with the YMP-204MS, their silver plated mellophone. They also sell a lacquered brass version of this lyre for the [lacquered] YMP-204M
Photos taken by me on a Nikon D7200 with a Nikkor 24-70 f2.8G lens at f/6.3, 1/80th, ISO-1000, with a focal length of 40mm (60mm equiv.). Honestly I should've broken out the D780 for that lens, I'm just more familiar with the D7200.
This is.... rather strange. Yamaha chose to add extra complexity to their design. In and of itself, that's fine, but it does mean that Yamaha has another accessory to produce, and it's an accessory only compatible with their horns. So not only do they have to provide it (no marching instrument is complete without a music holding solution), they can't count on selling more for people to use with other models of instrument.
They forced themselves to produce another accessory, an accessory which is exclusively used by their mellophones. I think this is a mistake, but it was Yamaha's decision. Maybe they just simply couldn't come up with another solution?
The Captive screw
This is where the design starts to suck- because not only is it a part that is utterly critical to the function of the instrument, it's a part I've seen fail in multiple ways and it is extraordinarily difficult to replace.
But first things first: what is a captive screw? Well, my dear human, a captive screw is simply a screw that once installed, isn't removable. The idea is you can make a screw that would normally be very easy to lose permanently attached to one of the two things it screws into/clamps. In this case, you don't need to worry about the screw coming lose and being lost on the marching field.
But there are many ways to make captive screws, and Yamaha's method is.... questionable at best. What they did is create a normal screw, but with an enlarged thread on the bottom. So once its installed it's 'impossible' to unscrew it- except that a dedicated idiot can actually remove one. I personally have removed one intact and reinstalled it, but I've also seen one be totally broken in an attempt to remove it. I've seen the head bend, locking the screw into the threads of the mount.
And that thread on the bottom can be damaged, leading to a screw that simply won't work with any lyre. And because of the enlarged bottom thread, it's not really a user-servicable part....
In fact, 3 of our 16 YMP-204MS Mellophones have damaged screws- one with a bent screw head which has jammed the screw, one where the enlarged bottom thread almost entirely broke off and wouldn't let any lyres fit into it, and one where the enlarged threads at the bottom won't allow any lyres to fit without physically filing the lyre down.
Lyre Issues
Well, those issues with the lyre mount screws are pretty nasty huh- surely the lyres are a better design.... surely
Well, I already mentioned how there are nickel plated and lacquered versions, right? Well, the nickel plated ones don't seem to be made with a lot of quality control because oh boy.... dimensions on the part that slots into the lyre mount vary IMMENSELY. I've seen ones where the sides are so wide they simply do not fit at all, and require 15 minutes worth of convincing with a file. I've bought 3 of them in my 4 years, and 2 needed to be filed down. Maybe I'm unlucky, but that number seems unacceptably high.
My Thoughts
Well, I think Yamaha messed up- but I cannot figure out a fundamentally better design for the mount. Ignoring the [idiotic and pointlessly complex] bends in the lyre, their design is fundamentally, rather good. But-
- their quality control on both lyre plating and the screws is unacceptably poor
- the screws should've been manufactured to be stronger and more durable
- the screws should have been designed in a manner where they're more easily serviced by players and bands
- would it kill them to sell replacement screws to the band directly???
Despite this massive failing, I still think the Yamaha mellophones are the best on the market- but this is still an issue plaguing a large portion of our mellophones, and we need to send them in for repair because of it. If you find this and think it's incomplete, shoot me an email. I'll (happily) integrate comments from others' experiences, especially if you have advice on how to repair a mello plagued by these issues.