Good starter euphonium
You are looking for a starter euphonium. The starters' instruments also come in many different degrees. The choice between a model with 3 or 4 valves doesn't matter much. In the beginning you play most with the 3 valves. You can also often choose from small or large drilling. The small bore will play a little lighter. But there and against the large bore has a somewhat fuller sound. You can also choose from gold or silver colored. This is mainly a taste issue. Maybe you will play at a harmony association? They may be playing on silver-colored instruments, for example.
There is also some sound difference. The silver may sound a bit fuller. But the differences are minimal. The most important thing is what you like! With us you can always try the instruments. Even if you can't play yet, it's nice to hold one. And already get the feeling.
New or used euphonium
A second-hand instrument is a good choice! It is of course important that your instrument is in good condition. This is sometimes difficult to assess. Buy your instrument with warranty. This way you always have the option to go back afterwards if you are not happy. You may be offered a nice instrument privately. For example via marketplace or another platform. It is wise to bring someone who understands it. You are also always welcome to have your almost purchased instrument assessed. That way you don't buy a cat in a poke.
What does compensated mean? This often remains a difficult topic. And how do you recognize it? And what does it do? If you have 4 valves, your instrument is not yet compensated. With a compensated euphonium there are extra tubes on the instrument. This makes the difficult tones easier to intonate. In this way you solve your intonation problems to a large extent. A compensated instrument is very expensive. A model with 4 valves often also solves many purity problems. That way you save yourself a lot of money. But if it fits in your budget, a compensated one is nicer.
Nozzle: Here you blow up. You create a tone through the vibrations
Valves: You press this to get other tones
Water valve: The valve is attached to a pump, this removes the condensation
Compensated: Extra tubes on your instrument so that the purity problems improve
Boring: This is the width of the tube that you blow through
Redemption: The basic material in brass and the layer over it is sometimes silver-plated
Harp holder: Here you can confirm your march booklet
Cup: This is where the sound comes out
Gigbag: This is where you transport your instrument safely
Tuning pump: Here you can tune your instrument