Let’s Talk Trumpet — Waterkeys & Dump Slides (Part I)

Do you have to rotate your entire instrument to dispose of built-up condensation? Do you have to pull out certain valve slides and blow out the condensation from there? Or better yet…do you have to blow into the bell end of your instrument to allow for condensation to empty out? Oh my!

One of the many hindrances that we, as brass players, typically face when playing our instruments is having to dispose of condensation that builds up inside the instrument. Having the right timing of when to empty out said condensation is another key factor, not to mention how one might have to do it in front of an audience.


3rd valve slide with dump slide

In the world of instrument manufacturing today, we can find that our instruments come equipped with either a waterkey assembly[ies] or a dump slide in order to dispense any built-up condensation. On trumpets, for example, waterkeys are commonly found on main tuning slides or 3rd valve slides, and dump slides are usually found on the ends of 3rd valve slide assemblies—depending on the make and model of the trumpet.

All manufactured brass instruments today come equipped with pre-installed waterkey assemblies; however, these assemblies may offer different means of operation. In R. Dale Olsen’s book, Chronology of Innovation: Volume I, Drainage Devices, he lists and describes the five different categories of drainage devices for brass instruments that we can find:

Passive — “JoyKey” Waterkey
  • passive — Andrew Joy “JoyKey”, etc.
  • lever — C.G. Conn [Sept. 16, 1890], H.N. White [Aug. 27, 1918], etc.; ex. Bach or Yamaha main tuning slides, etc.
  • rotating — Denis Wedgwood & Brian Gardner “Saturn”, etc.
  • push button — Ray Amado “Amado”, Jerry Pollard “Pollard”, etc.
  • sliding action — Frank Snyder [Aug. 18, 1914]

The first four categories are what we see more often on modern commercial brass instruments. On the other hand, sliding action waterkey assemblies, such as Frank Snyder’s, fell out of favor, likely during the early 1900s. As the sliding action waterkeys were primarily made to “…eliminate the use of forks [or levers] and springs…”, we can imagine that the level of maintenance and upkeep for these sliding action waterkeys was excessive and led to their decline in popularity.


We now look to waterkey designs and wonder: how could one develop a waterkey that can perform effectively while strategically positioning it onto the physical arrangement of an instrument? After asking ourselves this, we can dive deeper with the following questions:

  • Which design is most cost-effective for job shop manufacturers? For discrete production line manufacturers?
  • What design is most effective for dispensing condensation?
  • What design does not negatively affect the acoustics or overall dimensions of the instrument?
Lever – Bach main tuning slide

As we take these factors into account, let us start with the first question and review some of the economic factors that may tie into the manufacturing processes of these assemblies.

When it comes to discrete production line manufacturing, the push button and lever waterkey assemblies are being used more often and installed on trumpets made by big-name corporations today, due to the lesser costs and steps involved in the implementations of manufacturing and overall operations. On the other hand, job shop manufacturers (custom trumpet builders, etc.) are often more at liberty to use any type of waterkey assembly they see most fitting—which would include the rotating and passive style waterkey assemblies.

Now, regarding the last two questions in the list, these questions are intended to bring out players’ personal preferences, and what these players seek to achieve with the waterkey and its overall functional purpose. We will continue discussing these two questions in detail in the Part II segment of this blog post on Waterkeys & Dump Slides!


Olsen, D. (2018). Chronology of Innovation: Volume I, Drainage Devices (First ed., Vol. I, pp. 143-145). : The Horn Guys.

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