Booster or PreAmp. What is the difference

[seibertdr]

New to building pedals. Would like to know what the difference is and where would you put each into an effects chain?

Thank you,

Don

[Steben]

New to building pedals. Would like to know what the difference is and where would you put each into an effects chain?

Thank you,

Don

very very very little difference.
I've seen preamps with 1 transistor and booster with several ones. It fugures...
Usually "preamp" refers to complex design, with tone control, clean tones, ...
"Booster" usually means a pump of the level in order to overdrive the main amp.
As you can see, a preamp probably will be able to pump up the level as well, and many boosters actually have tone shaping.

An Eq pedal is a nice example: although it's just frequency shaping, many players use it to boost some frequencies into drive.
But try to think like this: a booster will never be made for subtle clean tones.

[petemoore]

  They call it what they want, and sometimes the designs work well..
  Pre-amp...transistor booster is called an 'amplifier' technically it amplifies...
  it's a bit like 'low cut boot' meets 'high cut shoes'..
 

[seibertdr]

Thank you for the answers. I do have am EH LPB-1 that I bought before getting into building pedals. I just wanted to make sure I wasnt doubling my efforts.

[Mark Hammer]

Been down this road before.

A "pre-amplifier" is something that brings the signal up to some expected level.  So, if you were reading magnetic tape with a tape head, or a vinyl disc with a cartridge, the "preamplifier" aggs gain to the signal so that the puny couple of millivolts or microvolts detected from the storage medium are sufficient to eventually drive a power amp, which will be expecting something in the neighbourhood of at least a couple of hundred millivolts.

Within the pedal world, many pedals will have preamplifier stages in them to compensate for passive loss through tonestacks and such; in other words to bring the signal back up to some designated level.

What gets "called" as preamplilfier is generally somethng that provides some gain without aiming for coloration, and supplements that with some EQ capabilities.  The Boss FA-1 is a good example of a preamplifier.

What gets called a booster is generally used to provide MORE than an anticipated level, rather than some expected level.  It also produces gain, and may in fact provide no more gain than a "preamplifier" provides, but the express purpose is generally to either a) permit "solo" and "rhythm" levels at the press of a footswitch (rather than involving taking your fingers from the strings and putting them on the volume pot), or to b) provide a much hotter signal to the amp such that something somewhere gets overdriven.  "Boosters" can often have, but do not necessarily have, some tone-shaping capability.

As was noted by others, there is really no difference between the circuits in most instances, other than their application.  In some instances, and I'll note the Klon Centaur here, the signal is not only boosted but clipped, EQ'd, and maybe even blended, expressly for the purpose of eliciting a certain quality of overdrive from the amp.  That is, the properties of the boost anticipate the behaviour of the amp, and boost in a particular way rather than simply applying unaltered gain.