#1
ok, so i am such a noob at electric guitars, but i want to get more involved with them.

first, what does the pre-amp do, just shape the tone and whatnot? so could you plug in a guitar skipping the pre, and going straight to the power amp?

and is there a difference between having the pre-amp in the guitar, and seperate, as in the head or cabnet?

thanks!!!
#2
A preamp takes your tiny little signal and makes it big enough to drive the output section. Tone-shaping circuitry, among other effects like reverb and tremolo, are implemented in the preamp section. You could run the guitar signal directly into a power amp, but it won't drive the output hard enough to hear much.

There are lots of differences that have been discussed in many threads on this forum. Try doing a search. Fundamentally, the location of a preamp doesn't matter.
#3
Quote by Losenger
You could run the guitar signal directly into a power amp, but it won't drive the output hard enough to hear much.


This is completely false. I play straight into my power amp all the time - the preamp has absolutely nothing to do with output (besides the additional volume control).
Won't drive the output, huh? I don't think you even know what you're talking about, of course you can hear it! The power amp is what (hence the name), amplifes your signal - all the preamp does is shape your tone (ie. EQ, clean/dist., FX).

/dignified rant
Last edited by DiMeTiMe at May 16, 2008,
#4
^Yeah. If your amp has an effects loop, plug your guitar into the effects loop return and your bypassing the preamp. I do it sometimes with my Classic 30, and its louder than i usually play at. Sounds pretty cool using the neck pickup of my strat copy
#5
Quote by littlephil
^Yeah. If your amp has an effects loop, plug your guitar into the effects loop return and your bypassing the preamp. I do it sometimes with my Classic 30, and its louder than i usually play at. Sounds pretty cool using the neck pickup of my strat copy




I like my cheap ass strat copy guitar too , but my heart resides within (literally,lol) my Godin Freeway Floyd .
#6
Quote by DiMeTiMe
This is completely false.
Incomplete truth? Yes. Completely false? Nope.

Quote by DiMeTiMe
I play straight into my power amp all the time - the preamp has absolutely nothing to do with output (besides the additional volume control).
Either this is patently false or you have a very unusual preamp. Preamps provide amplification of the signal (typically 10~100mV) from the guitar.

Quote by DiMeTiMe
Won't drive the output, huh? I don't think you even know what you're talking about, of course you can hear it!
Read the post. He didn't say it wouldn't drive the output. He didn't say you wouldn't hear it. He said you wouldn't hear much. This is reasonably true. You won't be able to drive any power amp that I know of to full output with just the signal from a guitar with most passive pickups. Actives, maybe. But even then, you won't be able to get to high enough levels to "crunch".

Quote by DiMeTiMe
The power amp is what (hence the name), amplifes your signal - all the preamp does is shape your tone (ie. EQ, clean/dist., FX).

/dignified rant
Ugh. Where do you think distortion comes from? It's from creating a signal so large that later stages are driven beyond their limits. Those later stages can be within the preamp itself, or in the poweramp. But creating that large signal takes amplification.

Another thing you failed to mention was impedance. Many poweramps have an input impedance of about 10k ohm. This would be a major tone suck on passive pickups. Because of the (internal) series inductance of the pickup, the low impedance load will attenuate the high frequencies.

There may be some rare instances where you can get by without a preamp, but in general, it's a poor idea.
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#7
You could get by without a preamp if you used a buffer to match the impedance. But then again, the buffer could be considered a "preamp," even with a gain of 1. Still, output amplifiers are meant to be DRIVEN, not trickled upon. Also, as SYK mentioned, increasing a signal requires amplification. Usually, the preamp is designated for this task, and the power amp's task is to drive a load.

And furthermore... active pickups in and of themselves are preamps.