What's the difference between "valve" amps and "solid-state" amps?

When it comes to buying the right guitar amplifier for your sound, the most common first question tends to be "Should you buy a valve amp or a solid-state amp?" We want to try and de-mistify this question as much as possible, as it is an important part of shaping your guitar tone.

Valve or "tube" amps work with traditional tech - the sort of technology you'd find in a vintage TV or stereo.  These amps give a round, warm, and reactive tone which can be smoother and easier to control than the tone of a solid-state amp. They can be more expensive due to the nature of construction, and often have less features than a similar solid-state amp and tend to require more upkeep in terms of infrequent valve replacement. However, these types of amps will last longer, because they tend to be repairable. Valve amps are a huge favourite amongst the more traditional rock or blues guitarist!

Solid-state amps have been around since the 60's, but are constantly evolving and improving.  They work using transistors and diodes to provide power and tone, with more modern amps basically operating as a computer, allowing you to edit your tone and add effects.  While technology is constantly improving, many tone purists can hear the difference in tone and response when listening to a solid-state amp, but in many situations, such as wanting to play at low volume, having many tones in one amp, and affordability, solid-state amps often win out.  Solid-state amps require far less upkeep than their valve counterparts, but often do not have the lifespan, due to the difficulty of repair.