A limiter is like compression but instead of squashing the signal it just cuts it. It limits the signal from going above a certain volume. Good for when you have some pieces of gear that are sensitive to high input levels. It is also good to avoid digital distortion when going into the digital realm with recording.
aka Izabella
So.. The point in getting a power-amp and/or pre-amp would be pointless if you were using a amp head?
Mostly. Active pickups need their own preamp (usually battery powered and built in to the guitar), and you might want to put a preamp in front of some effects. You could use an effects loop for that, or use a seperate one. You might also want to pair a different preamp with a power amp you like.
An amp "head" is both a pre-amp and power amp in one chassis.
As described, pre-amps are the interface you deal with on every guitar amp.. tone, presence, bass, midrange, gain... the power amp section is just that... its only responsibility is powering speakers. This is why seperate power amps having nothing but a power button, and 2 volume knobs in many situations (sometimes not even that)
The reason you see people with such extravagant rack systems is because of a few reasons...
1. Most higher end heads or pre/power combos do a rather limited range of things. They wont have reverbs and normal effects on them, so that work needs to be done by some other piece of equipment. On that same note, most "do everything under the sun" processors are also a jack of all trades, master of none deal... so if you see someone using a dbx compressor, that is ALL that piece does, is compress, and it probably puts that effect on better than the built in compressor on something like a Pod XT, for example.
The ultimate goal is to put effects and whatever tonalities are needed into a guitar rig, and make them as "transparent" to your original tone as possible... you'll notice that stacking things in your signal chain starts to alter an amps pure tone, and lots of people will go to great lengths to reduce this.
2. Redundancy... lots of pro rack systems will include 2 of some things... if a crucial piece decides to stop working, there cannot be much delay in getting that persons sound up and running again.
My rack is in my signature.it is comprised of
bottom to top:
pv-2600 watt amp(mids & Highs)
Pv-1500 watt amp(subs)
Peavey Kosmos Enhancer, and crossover
Peavey 15 band equalizer
Dual wireless receivers
lighting controls
Power conditioner
Computer
Mixer board
in the back of the rack I have
2 wireless mics.
tv Modulator
