Gain vs Volume

you know? that's a great question!
I have always owned amps without Gain. they were just plain old tube amps. On/Off, Vol, Vibrato, Reverb.
when I jam with others and plug into a different amp, I never really know what to dial.
Master? Gain? Vol?
yeah. great question.

There will be a lot better explanations (and better detailed, as well) than this, but it should get you started:
Essentially, amplifying your guitar is a two-step process. The signal sent from your pickups down through the cable to the amplifier goes first into the preamp, which boosts the signal and shuffles it over to power amp. The power amp then magnifies the input from the preamp immensely and sends it out the speakers. This is a very watered-down explanation, but being aware of the two stages of amplification will make dealing with your amp a lot more logical.

Usually an amp will have two channels, or signal paths. The first is called “clean,” and here the preamp signal goes directly to the power amp. You control the output of the power amp with a volume control. In the second channel, you get to dictate the volume of the preamp signal. The preamp adjustment is often labeled as “gain” or “drive.” Increasing the volume of the preamp introduces more distortion to the signal, giving you that warm crunch that rock guitarists thrive on.

Hope this helps.

Peace

I'm glad you asked this question. I'm not a beginner on guitar, but am definitely a beginner on PAs and amps. On my cheap practice amp, there's a gain control and a volume control. On my Carvin Stagemate PA, there's a master level and a level for each channel. The manual for the PA seems to use "gain" and "volume" interchangeably.

Both the amp and the PA have level controls for high, mid, and low. I generally start with everything on the amp or PA set in the middle and the guitar volume set low and then tweak the guitar volume until I get the level that I need. I also adjust the high, mid, and low on the amp or PA for the balance that I want. If I start to get feedback, I back off on something, but am never sure what I should lower first.

Things get more complicated when I use a guitar with a preamp. Should I be leaving the levels on the PA at the middle settings or an even lower setting and adjust the preamp on the guitar?

Just to clarify, I am almost always looking for a clean sound without distortion.

In a technical sense, "Gain" and "volume" are interchangeable, and "gain" is the more accurate term. But as used on guitar amps, "gain" is usually used to refer to a control on an early stage of an amp and "volume" to the last stage. Sometimes they're labeled "Volume" and "Master Volume." You can use the "gain" to adjust the amp's sensitivity to pickups with different output levels. Often it's used to overdrive an intermediate stage of the amp to distortion, and then use the "volume" or "master volume" to keep the sound level down to where your ears don't bleed. Play with the two and you'll find a broad range of tones and amp response.

And don't forget that the tone and volume controls on your guitar are there to be used, not just cranked all the way up and left! The old school way of doing things, which I find most useful, is to crank up the gain, volume and tone controls on your amp to the most you'd ever want or a little bit more for a playing session, then turn down your guitar's volume and tone for where you want it to start. You can turn them up and down as desired as you play, and it adds a dimension to your playing.

Hope it helps:

http://www.youtube.com/watch?v=yP1Rfb5AyD8

The explanations you guys posted were pretty good ,as was the youtube video,at clearing up the difference between pre-gain(I think "drive "is a more descriptive term) and volume. .But I'm still in the dark as to the difference between post-gain and master volume.

Master volume is for multi chanel amps so you can raise or lower the overall volume without changing the relative volume of the seperate chanels. Post gain is made to interact with the pre gain to change the sound by increasing or reducing overdrive. The master volume is not meant to be interactive, it is meant to be clean. I have a couple Peavey VYPYR amps. I have the 15 and the 75. They are cool amps.