Concert Sound

How come when guitarists play live with there overdrive channel selected and the gain on 10, how dont they get ugly noises and stuff, just from the fingers touching the strings? when i have my marshall up half way its hard not to get loadsa sounds coming out of it!
And at concert volumes- how dont they always get feedback, the pickups must hear the massive volumes of sound generated, or do you just primarily have to be ner the amp for feedback?

I think its because they use a lot of noise gates, filters, and compressors that essentially block out all unwanted noise.

Probaly a couple of reasons, Less pre-amp gain, a maxxed out preamp will squeal like a pig even if the masters on 1,
Potted P/U's, at high volume even the windings in the pick-up can vibrate, so the pick-ups are soaked in melted wax/parafin to kill the vibration, Careful use of the guitars volume knob, if you ain't playing, turn it down, palm muting helps, tech stuff like James mentioned, cabinet/speaker placement, finding the right amps, etc, etc, etc, and possibly it's because they are magic........

I have the marshall valvestate 100. Channel volume and master volume. Whats the difference between the channel volume on 1 and master on 10, compared to the channel on 10 and master on 1? is there a difference. And what do you mean by pre and post amp? Could you add the 'gain' to the sound via a effects pedal instead thus reducing break up? beacuse the pickups wouldnt be picking up that when you are playing?

The Channel Volume controls the level of the preamp for that channel. The Master Volume controls the drive level into the power amp, which affects the total loudness. With the Channel on 1, and the Master on 10, there would be very little music coming out of your speakers, but since the power amp would on full, there might be quite a bit of 'hiss'. With the Channel on 10, and the Master on 1, that channel of the preamp would be up full, (and probably distorting), but the power amp would be sending very little power to the speakers, so you would hear a quiet, but distorted sound.

'Pre' and 'Post' refer to the position of the tone controls relative to the gain stage. 'Pre' controls the tone settings before the signal gets boosted; 'Post' works on the sgnal after it gets boosted.

'Gain' is the amount of boost or amplification that is applied to the signal. Unless you have active pickups, with a preamp built into the guitar, all the guitar controls can do is reduce the amount of signal that comes out of the guitar. From there, gain is applied at any point in the signal path that you want it.

There is alittle difference between tubeamps, hybrid and
solid state amps too...