Is boosting an amp like turning up the bias?

[asdfdsa]

Is running a boost pedal in front of amp (increase gain/power/signal) similar to increasing the power bias? since in effect they are both raising the power to the power tubes.

 

[rickc007]

No, just makes the siganal larger

 

[kevinhifi]

Hotter bias will push the power section harder and get clipping/harmonic distortion out of your power tubes at lower volumes.

Putting a boost in front of the amp will push the preamp section harder and get clipping/harmonic distortion out of your preamp tubes.

The popular trick is to get a vintage or vintage-inspired amp to the point of just starting to break up (on old Fenders, that's usually a combination of preamp and power section starting to overdrive) and THEN hit it with a booster up front. That way you end up pushing both the preamp tubes and power tubes a little further into distortion, which is a nice sound.