Like lightbulbs, valves don’t last forever. Eventually they need to be replaced, and this is why they sit in sockets you can easily pull them out of.

In a typical amplifier there are two types of valves: the smaller ones which take the small input signals and increase them to drive the final stage. These valves should last forever.

The output valves are a different story. If you look closely you will see that there are usually four larger valves – these do the much of the heavy lifting. Different manufacturers will specify different lifespan figures, but much of that will depend on how they’re used.

The guidance we give customers is to expect between 7500 and 10000 hours of operation from a set of new output valves.

This is much longer than in guitar amps – the reason being, in hi-fi, we are not overdriving them.