What's the difference?

[Wild E]

Just curious what the difference is between a preamp, a booster and an overdrive.

[Earthscum]

If I'm not mistaken, it's about implementation. I think a true "Preamp" is meant to boost the entire signal amplitude, but not color the sound in any way. A booster is a preamp with some frequency shaping, usually. An Overdrive is basically a light distortion. A booster will 'overdrive' a tube amp to cause distortion, however an "overdrive pedal" actually overdrives an internal circuit, causing slight compression and distortion... a lot of the time to emulate, somewhat, an overdriven tube amp.

[davidallancole]

To me:

Preamp - Everything before the power amp.  An example of a pre-amp pedal would be the Boss Metal Zone 2.

Booster -  Anything to increase the level of your guitar signal, without clipping the signal.  It can change the frequency response of the guitar signal though, just no clipping.  A couple examples of boosters would be the EH LPB (linear) and Behringer PB100 (has equalization).

Overdrive -   I think Earthscum explained that one all right.

[Earthscum]

Aye, I forgot to say... generally a preamp is used to boost the signal to a line level (about 1V). http://en.wikipedia.org/wiki/Line_level

Like david said, it's used to drive a power amp... also mixers and other equipment that utilize line level signals.

[petemoore]

  That depends on what is behind the label.
  Also what the device is intended for sourcing/driving.
  A booster can overdrive [something].
  A preamp can overdrive [something].
  An overdrive may be part of a preamp.
  Preamp may have a boost or bass boost.
  I think that's part of a tip of an iceberg of terminologies, misnomers and uneducated guesses. Try the manuals, they sometimes have accurate terminologies, spec sheets are usually even better that way.

[Wild E]

Wow Petemoore, it's kinda scary that you and I are on the same wavelength, your comments seem a bit cryptic to me sometimes and have info I don't understand yet, but you pretty much nailed what I was thinking on this one!
I had the booster pegged as clean but I had to include it because;
1. all three ckts. boost the signal (are amplifiers)
2. all three ckts. will overdrive an amplifier
Here are my current definitions (in their simplest form)
A booster is a relatively clean preamp.(LPB1)
A preamp can introduce distortion through it's transistors or valves.(as in a tube preamp)
An overdrive is a preamp that introduces distortion via it's transistors/valves/opamps and or external means (clipping diodes)as in my
DOD
OVERDRIVE
PREAMP/250
So now my next question,
where is the fine line between overdrive and distortion?

[davidallancole]

A pre-amp to me is a front end to a power amp.  Everything back from the master volume in a JCM 800 is the pre-amp.  A Boss Metal Zone 2 is a pre-amp.  A Radial Tone Bone is a preamp.  They all create distortion and have equalization in them.  They have the ability to create a full sound independant of the overdrive/distortion inherent in an amplifier.  They are the types of things that sound best feed into the effects return jack as opposed to the input.  Pedals like the Metal Zone 2 sound like crap through an overdriven amp.  They need a clean power amp.  Where as something like a Tube Screamer takes an all ready overdriven amp and pushes it futher.