Amps for Total Begin­ners

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When I was putting on gigs I used to produce zines with the list­ings and a beginner’s guide to vari­ous aspects of making your own music. One of the other articles about pedals can be read here.

Amps for begin­ners

If you are play­ing an elec­tric guitar or bass, you will need an amp. Here’s a guide to how they work, and how to find the one that will suit you.

You need a specif­ic amp designed for the guitar or bass. Guitars will often sound bad and muddy through a bass amp, and play­ing a bass through a guitar amp can damage it, because it’s not designed for such low frequen­cies. Even if it doesn’t get damaged, it won’t have that full, rich sound you’re look­ing for.

The science

The pickups on the guitar are magnets wrapped in wire. This creates a magnet­ic field. When you pluck the strings, it changes and disrupts the patterns of the magnet­ism, which turns into an elec­tric­al signal, trans­mit­ted via the cable. Of course you can’t hear this, so you need some­thing to turn it into a sound, which is where the amp comes in.

The preamp circuit in the amp turns the very weak signal from the guitar into some­thing usable for audio, and then the power amp circuit turns it into a LOUD sound that can be played on the speak­er. 

Differ­ent types of preamp circuits in the amp give the sound very differ­ent kinds of char­ac­ter, and the well-known brands of amps all have their signa­ture sound. Using the wrong amp for the sound you’re trying to achieve can be really counter-product­ive.

Tubes and solid state

There are two kinds of tech­no­logy used in guitar amps- valve and solid state.

Vacu­um tubes or valves are the older kind. The current is passed through sever­al large glass vacu­um tubes to ampli­fy it. Although the tech­no­logy has been super­seded, many people think the sound is warm­er and rich­er, and still prefer to use valve amps. They also have a very distinct­ive warm distor­tion sound when the volume is cranked up high. 

A valve amp needs more care­ful look­ing after- the tubes need time to warm up before play­ing, can get very hot in use, and can’t be moved while they’re still hot. You also need to be more care­ful moving the amp to not damage the glass inside. It’s also a good idea to have a spare set of replace­ment valves for when some­thing goes wrong.

Solid state or tran­sist­or amps use modern elec­tron­ics and are more conveni­ent. There’s no glass to break or over­heat. A lot of people don’t find the sound as satis­fy­ing as a valve amp though. Many solid state amps now come with effects and amp model­ling built in. This means there’s a digit­al filter that tries to make the amp sound like differ­ent clas­sic amps. Wheth­er this is success­ful or sounds good depends on the specif­ic model of amp and your person­al tastes.

Useful inform­a­tion: Every­one hates the Line 6 Spider Amp. They’re every­where though, and lots of music shops throw one in almost free with a guitar. It’s a solid state amp with an unpleas­ant basic clean tone and the CHEESIEST digit­al effects

Combos, Heads and cabs

There are also two basic phys­ic­al forms of amp- combo and head+cab.

Combo amps have the amp circuitry and speak­er in one unit.  You can get small ones for prac­tice at home, and large ones for perform­ance. On stage a combo amp will often be miked up- a micro­phone will be placed in front of it so the sound plays via the PA as well as through the amp speak­er. This is the best place to start for a begin­ner and for play­ing at home.

Heads and cabs are two separ­ate units. The amp head handles the ampli­fic­a­tion, and it’s then connec­ted up to separ­ate speak­er cabin­ets. This is more flex­ible, because you can choose differ­ent speak­ers with differ­ent sound char­ac­ter­ist­ics and use BIG speak­ers. (One speak­er is known as a half stack, and a pair one above the other is a full stack). Most people also choose this because it’s REALLY LOUD. Smal­ler venues will often not mic up large speak­er cabs- they’re already loud enough.

With cabs, make sure to use the special speak­er cables to connect them up, rather than guitar cables. They look very simil­ar, but are differ­ent specs, and you could find everything suddenly not work­ing (or worst case, melt­ing) because you used the wrong cables, and they finally gave out.

Of course this is a more expens­ive option, and you will also need a prac­tice amp to use at home to make sure your neigh­bours don’t hate you. You really don’t need a full stack if you’re not play­ing live. There is also the issue of who will carry it up the stairs and how you trans­port it.

(And when you see foot­age of stadi­um bands with a million cabs behind them, often a lot of them are fake boxes designed to look like a speak­er to make the stage look cool- usually only the top row is actu­ally connec­ted).

There are also rack-moun­ted sets, but we won’t go into them, because that’s more of a stadi­um setup.

Some people who are really devoted to amps use multiple amp heads simul­tan­eously via a split­ter pedal. You can create a really good sound and tone this way, but of course it’s very expens­ive and you’ve got to know what you’re doing to connect it all up correctly. You can’t just get a split­ter cable- you need the elec­tron­ics of the pedal. Our friend Tanya who plays in Bismuth and Dark Moth­er has up to five amp heads in play.

Amp etiquette

Often people are kind enough to lend equip­ment. Don’t assume- ask politely in advance. This usually applies to cabs and combo amps. Most people are more precious about their heads. Make sure all cabs are connec­ted right (see ohms) and don’t crank it up without permis­sion.

Speak­er sizes

The speak­ers on combo amps and cabs come in differ­ent sizes. Bigger speak­er cabin­ets usually have multiple smal­ler speak­ers under the cloth rather than one giant speak­er. The spec of the speak­er cab unit will often be expressed in how many there are of each type of indi­vidu­al speak­er- ie 4×12”

6-8”– very small speak­ers for guitar prac­tice amps
10”- punchy high­er sound for guitar, and often used on bass amps too
12”– stand­ard for stage guitar amps. Big cabs typic­ally have 4×12” speak­ers
15”– a monster. Usually found on giant rumbling bass amps


The power of the amp is usually meas­ured in watts, the high­er the number the more power­ful. Sounds simple? It gets a little confus­ing, as solid state and valve amps are rated differ­ently, and combos and heads come out differ­ently. As do bass and guitar. So I will split them up by category:

Solid state:

Under 30W– home prac­tice amp

30-60W- for prac­tice and small gigs

60-100W– stage amp

200W– bass stage amp (bass amps need to be much high­er watts than guitars on stage)


Under 10W– home prac­tice amp

10-50W– for prac­tice and small gigs

50W+ – monster

Using a head and cabs also makes a differ­ence. Using a low watt valve head with some big speak­ers can be very very loud. The bigger the speak­er, the louder everything is too.

Crank­ing it up

This is also where the differ­ence between valve and solid state amps come into play.

Basic­ally valve amps sound good at near maxim­um volume, and solid state amps gener­ally don’t. Using a smal­ler valve amp and crank­ing it up high will have a smooth distor­tion sound, where­as a small tran­sist­or amp up high is harsh.

This is anoth­er reas­on why the wattage categor­ies are differ­ent for the two types of amp. A 20W valve amp can sound really good on stage turned up high, but with a solid state amp you are better off having a larger amp at medi­um volume.

High and low gain

Larger amps often have high and low gain inputs. The high gain option ampli­fies more and gives a “hotter” sound more prone to distor­tion. The low gain input is clean and smooth.


Elec­tric­al resist­ance (or imped­ance) is meas­ured in ohms- Ω. You don’t have to worry about this if you’re using a combo amp. However it’s import­ant when plug­ging cabs in. Too much or too little resist­ance in the circuit can ruin equip­ment- espe­cially when using a valve head.

Each speak­er has an Ω rating. Your head output has to match (there’s a switch to adjust it). If you use one 4Ω speak­er, switch the amp to 4Ω. Simple.

If you’re using multiple speak­ers, then you need to be more care­ful:

Speak­ers in sequence (“series”): You’re essen­tially send­ing the current uphill, so need a stronger signal- so two 4Ω speak­ers needs an 8Ω signal- you ADD the ohms

Connec­ted separ­ately (“paral­lel”): This is the oppos­ite- two 4Ω = 2Ω output- you DIVIDE by number of cabs

If someone is gener­ous enough to lend their cabs, get them to help you set them up right. It’s really not much fun blow­ing up someone else’s gear.

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