Having a great guitar amp might just be more important than having a great guitar. Sure both are important but you can sometimes plug a poor quality guitar into a great amp and have it sound good but a great guitar plugged into a terrible amp still won’t sound that good.
There are basically four types of guitar amplifier and each has its own strengths and weaknesses.
Tube amps – The tube amp has been around the longest and is the amplifier that all others are modeled after. A tube amp uses glass vacuum tubes in its power section and preamplifier section. Because of the tubes, these amps have a warm tone that feels natural and offers a lot of sustain and power. The drawback to tube amps is that the tubes wear out over time and as they wear out, the sound of the amp changes. Tube amps also store a lot of voltage and therefore require a specially trained technician to change the tubes every few years.
Solid state – The solid state guitar amp has the benefit of sounding the same every time it’s switched on as it doesn’t rely on parts that wear out to create its tone. A solid state amp uses transistors in its preamp section rather than tubes. While this does make the amplifier slightly more reliable, the tone is generally grittier and more sterile especially on overdriven or lead tones. Solid date amps almost always cost less than tube amps.
Hybrid – The hybrid amp is a new breed of amplifier that blends a tube preamp section with a solid state power amp section to try to achieve the much desired tube tone. Marshall started this trend with their Valvestate line of amps and Line 6 has partnered with world renowned tube amp manufacturer Bogner to create a modern hybrid amp. A hybrid amp naturally costs a bit more than a solid state amp but are still less expensive than a high quality tube amp.
Modeling amp – These are amplifiers that have a digital processor built in that attempts to replicate the sounds of many different guitar amplifiers, cabinets, rooms and microphone placement. They are very flexible and usually have effects built in as well as a tuner, and a direct line out for recording. Most can be switched via a foot controller so that different sounds can be brought up on the fly. They are versatile amplifiers that can generate many different sounds and are getting closer to sounding like tubes amps all the time, but many are just not there yet.