what are preamps?

[gordonzz]

what are preamps? if i to record a bass track (i am using computer to record) do i just line it in?

[bigwillz24]

Preamp is short for Preamplifier

From Dictionary dot com:

An electronic circuit or device that detects and strengthens weak signals, as from a radio receiver, for subsequent, more powerful amplification stages.


My broad definition:

A preamp raises the line signal so theres less room for noise before it goes into your recording device in this case your computer.

[darknailblue]

Most preamps give some amount of tonal control like EQ settings and what not. All guitars and basses have preamps in them too. The volume and tone controls on a guitar is a preamp. When your recording bass... depending on what kind of bass you have, you might not even need a preamp. This is because an electic bass is predominately meant to be played clean and the majority of the sound comes from the bass. With guitar (at least as far as rock guitar playing goes).... the sound is majorily from the amp (listen to the radio and tell me how many of today's 'hard rock' bands use triple rectos). If you have a good bass you might be able to record just using a DI box.

~darknail

[Farview]

The passive electronics in most guitars are not preamps. If it has a battery, then it has a preamp.
To answer your question.
1. a preamp is what raises a mic signal to line level so it can be recorded or otherwise processed by equipment that expects a line level signal.
2. In guitar and bass terms, a preamp could be a device that gives you distortion and tone control. You have to plug this into a power amp to make a speaker cabinet work.
3. The front half of you amp head, if it is a tube amp, the part with the 12ax7s. This conditions the signal for the power amp which drives the speakers.

[darknailblue]

The passive electronics in guitars are preamps. Whether on not they are good ones or not is questionable, but they still are preamps. Plug a guitar into your computer, or a mixer and strum it a few times. EVEN with passive electronics, you can get the guitar to clip if the volume is all the way up.

~darknail

[Farview]

There is no amplification in pasive electronics, that is why it is called passive. There is nothing but 2 variable resistors and a capacitor that shunts high frequencies to ground. The power you get is from the pickup, it is not amplified in any way. The signal is that strong to start out with.
In order to amplify a signal, you have to run it through an amplifier, a pre amp, is the amplifier before the amplifier. If your guitar doesn't have a battery in it, it does not have a preamp.

[5 String]

Guitars produce a tiny signal, mics even smaller, and this needs to be magnified before it can be used.
This magnification is done by electronic amplifiers and it is done by stages.
The pre-amp is the first stage in a chain of amplifier circuits.

Sometimes a pre-amp stage is fitted inside the instrument.
This is called an active instrument.

'Traditional' guitars like Strats and Les Pauls usually do not have a pre-amp in them, just a resister capacitor network to attenuate (cut) the signal and to reduce the higher frequencies in the signal produce by the pickups, as mentioned above.
These are known as passive instruments.

There will still be a pre-amp involved with the use of a passive instrument.
It will be the first thing the signal 'sees' after is passes through the input jack of the device (amp, mixer, soundcard) you are using.

When you see 'Passive' and 'Active' OR 'High' and 'Low' inputs on a guitar amp you're looking at inputs designed to be used with 'Active' instruments and 'Passive' instruments.
They are designed to accommodate the different sized signals they produce and also match to the different impedances.