Ampeg SVT Bias ajustment

[RobbieNuke]

I replaced a power tube in my SVT (late 70's model). In the past I've always adjusted the bias per the instructions stenciled on the chassis (i.e. to 0.72v between K1 and GRD; 0v between K1 and K2). I am currently running RCA branded Sylvania 6550 power tubes. Can I set the bias to a different value for slightly more power?

[B-string]

Yes you can. A strict voltage adjustment is a "safe" bet but tubes vary. Less negative bias a little warmer, more negative bias more power but can get cold sounding. Dissipation or crossover notch adjustments work best but require a more detailed process.

[beans-on-toast]

By slightly more power, are you asking if adjusting the bias will make the amp louder?

A bias adjustment won't do that. As B-string said, varying the bias can make the amp warmer (distort sooner) or cooler. If you want more distortion, you can try a pedal like a Tech21 VT Bass pedal.

If you want more volume, you can add a second speaker cabinet.