[Addison]

Hi, I’ve been playing acoustic guitar for six or seven years now and electric for about a year-and-a-half. The amp I’ve been using so far is the one that came with my bass guitar, a little practice amp. I’m looking into buying an amp for church and (hopefully) gig use with my electric. I’ve read some of the posts on here, but there are some definitions I need explained first:

1. What is a “stack” or “half-stack”?
2. What is a “head”?
3. What is a “combo”?
4. What is the difference between an “amp” and a “pre-amp”
5. How do you choose cabinet size (ie 1x10, 2x12)
6. Should I be concerned with choosing between “Class A” and “AB” amps?
7. Why would I need a speaker and an amp?
8. Why do some players mic their amp? Does it really make that much difference?
9. Are some amps better suited to certain styles of playing (I play rock, classic rock)?

I know that’s a lot of questions, but thanks in advance for your help.

[Rainer.]

1. Traditionally, a "stack" is an amp head with two 4x12 cabinets (speaker cabinets with four 12 inch dia. speakers). A "half-stack", in turn, is an amp head with one 4x12 cabinet. Any head/cabinet combination could be referred to as a "stack", so often the two 4x12 combination is called a "full stack".
2. A head is an amplifier which does not have speakers. It is used to drive speaker cabinets.
3. A combo is an amplifier with the speakers built-in. It is one unit, rather than seperate amp/speakers.
4. An "amp" generally refers to the combination of a "preamp" and a "power amp". The preamp boosts the guitar signal and usually shapes your tone through EQ. The power amp takes the low level signal from the preamp and boosts it to send a signal strong enough to drive the speakers.
5. Different cabinet sizes respond differently in plying situations. Generally, the more total speaker area you have, the more the sound will spread through a room. Also more air is moving, and thus more speakers boosts percieved volume. As far as the size of each individual speaker, speakers usually come in 8", 10", and 12" varieties. Amps with more than one speaker will usually come with 12", aside from your odd 2x10" or 4x10", larger speakers have more bass response than smaller speakers, but the 10" combinations seem to have enough bass response on their own.
6. You should be more concerned about choosing the amp which is right for you. Nearly all higher wattage amps (30W and up) are class AB. Class A amps are low wattage, and have a very specific tone to them. If you like the tone, then go for a class A, but I find them to be very much a niche amp.
7. You wouldn't need additional speakers if you have a combo, but if ou get an amp head, you'll need speakers.
8. Players mic their amps onstage because an amp by itself isn't very good at spreading sound to an audience. Since the room's PA system is designed to spread the sound to the entire audience, the amp is miced by the player so that it is spread by the PA.
9. Yes. The amp is probably the single most important factor in your tone when considering musical style. More important than the guitar, even.

[Addison]

Thank you Rainer. That was very informative. I'll keep all this in mind when I go to the store next time.

[tht00]

Originally Posted by Addison

Hi, I’ve been playing acoustic guitar for six or seven years now and electric for about a year-and-a-half. The amp I’ve been using so far is the one that came with my bass guitar, a little practice amp. I’m looking into buying an amp for church and (hopefully) gig use with my electric. I’ve read some of the posts on here, but there are some definitions I need explained first:

1. What is a “stack” or “half-stack”?

Full stack:
http://www.harmony-central.com/Produ.../000000678.jpg

Usually, stacks consist of a head and 2 speaker cabs. Half-stacks consist of a head and 1 speaker cab.

A stack usually consists of a head

Originally Posted by Addison

2. What is a “head”?

The head is the circuitry that actually does the amplification of the signal to a level that can drive a speaker. They don't contain speakers, only supply jacks to connect to speaker cabs.

Originally Posted by Addison

3. What is a “combo”?

A combo is an all-in-one amplifier. It contains all the circuitry to amplify and it has a speaker.

Originally Posted by Addison

4. What is the difference between an “amp” and a “pre-amp”

Preamp has several meanings. The most generic explanation is anything that works with the line-level guitar signal (anything before it gets amplified by a power amp). Distortion/effect boxes and modelers could be considered preamp units because they are 'before the amp'. Not the best explanation, but easy to understand.

Originally Posted by Addison

5. How do you choose cabinet size (ie 1x10, 2x12)

Preference? What you need?

Originally Posted by Addison

6. Should I be concerned with choosing between “Class A” and “AB” amps?

Not extremely. In tube circuitry, class A is more inefficient (less watts per tube), although it is usually attributed with a sweeter tone. AB is more efficient, getting higher wattages.

Originally Posted by Addison

7. Why would I need a speaker and an amp?

Well, if you've got a head unit, it's got to be plugged into a speaker (or some sort of load) before it is powered up, or you'll blow the output transformer and who knows what else.

Really, I'd consider the head and speaker cab together a full amplifier.

Some combo amps have speaker outs that allow you to hook into a bigger speaker cab.

Originally Posted by Addison

8. Why do some players mic their amp? Does it really make that much difference?

There are several reasons to mic an amp. It's a good way to control stage volume and easier to control the main mix. Also, it allows smaller amps to 'hold their own' in louder situations.

Originally Posted by Addison

9. Are some amps better suited to certain styles of playing (I play rock, classic rock)?

Absolutely.