Micro BR Preamp setting

[FuzzFace]

Can someone kindly provide a technical explanation of what the preamp setting within a given effect is simulating?

In the non-digital world, I have only ever just plugged my guitar into a cheap amp and started playing... never mucked with preamps.

[dasilvasings]

I'm not an expert myself, and hopefully someone will correct me/ add more stuff.

Your cheap amp is in fact a pre-amp + speakers.

For large pro systems, they separate (physically) the pre-amp from the speakers. speakers are speakers, there are changes on the size of the woofers, arrange, etc. but all the meat is in the pre-amp.

Pre-amps have whatever the manufacturers put in there. Usually there is volume, gain and tone, but some have eq, compression, etc.

Note that (please someone correct me if i'm wrong) there is no distortion effect. You get distortion from having a big gain in the pre-amp, and that's how that marshall sound etc. is obtained.

Do not confuse the true distortion describe above with distortion stomp pedals that electronically create distortion before the signal goes to the pre-amp (if you have a big gain on the pre-amp, you get twice the distortion....).

So, on the micro-br, you have a couple of pre-amp models (there is a thread somewhere that tells you each pre-amp is which (marshall, mesa b., vox, etc. ), and the parameters available are the ones in the real pre-amp they are simulating. I suppose you also select the speakers arrangement.

The thread is here:

https://songcrafters.org/community/index.php?topic=862.0

[64Guitars]

The preamp effect simulates the characteristics of various guitar amplifiers using digital modeling techniques. See this message and this WikiPedia article.

[dasilvasings]

OK, I'm bit confused myself...

What we are calling "pre-amp" is in fact the "amp-head".

Usually in the circuitry o the "amp-head" there is a pre-amp and an amp. The "gain" is the volume of the circuit-pre-amp and the volume is the volume of the circuit -amp. You get distortion because the volume of the circuit-pre-amp saturates the sound, which is then amplified by the amp circuit.

I think this is it.

[64Guitars]

Amplifiers typically have several stages of amplification, with each stage amplifying the output from the previous stage. The two main stages in a guitar amplifier are the preamp and the power amp. The preamp takes the low level signal from a guitar and boosts it a bit. It includes the tone controls, etc. for adjusting the sound to personal preferences. The output of the preamp is still relatively low, so it is then fed into the power amp section which provides a much larger boost to drive the loudspeakers. The power amp section has no controls. It merely amplifies the output of the preamp to make it loud.

As DSS said, distortion is created when the output of one stage is too high for the input of the next stage. In a guitar amp, increasing the preamp gain causes the power amp to distort. Additionally, some preamps might have two stages, so that overdriving the first stage distorts the second stage and this distorted signal is passed to the power amp. I think "preamp" in the BR is a bit of a misnomer since it models the overall amplifier, including the distortion produced by overdriving the power amp input. Most BRs also have a separate Speaker Emulation effect which is used in conjunction with the amp modeling. But I noticed that the BR-800 combines amp modeling and speaker emulation in a single effect called "AMP". I think that's a good idea.

[dasilvasings]

Cool, so I'm starting to understand the thing!