Gain staging and signal to noise

[Oobly]

Hi guys, this seems like a good place to ask a question I have about gain staging.

I have read that setting up the gain staging correctly means I have every component set up to give maximum usable signal before clipping. If I set it up that way through the whole set of components (bass, preamp input pad, preamp gain, preamp output level, power amp attenuator) I will then get the maximum clean volume from the whole rig, right (assuming the cab can handle it)?

Which control should I then use to control my volume / bring it down to the level I want it at? Will using the power amp attenuator give me the best signal to noise ratio?

[Bassmec]

Originally Posted by Oobly

Hi guys, this seems like a good place to ask a question I have about gain staging.

I have read that setting up the gain staging correctly means I have every component set up to give maximum usable signal before clipping. If I set it up that way through the whole set of components (bass, preamp input pad, preamp gain, preamp output level, power amp attenuator) I will then get the maximum clean volume from the whole rig, right (assuming the cab can handle it)?

Which control should I then use to control my volume / bring it down to the level I want it at? Will using the power amp attenuator give me the best signal to noise ratio?

The whole point of best gain staging is to cause all the pre amplifier and processes to operate at best performance from the start of the chain to the end, at which point the signal may be attenuated to taste.
If you then turn down the bass guitar volume, there goes your signal to noise and careful gain staging.

[billfitzmaurice]

Maximum undistorted volume often means having the master volume full on. But that can result in more noise. The highest S/N will usually come with high gain, but that can result in high distortion. With a typical bass amp set the gain control for the desired distortion level, the master for output volume, and don't worry about noise as it's less of a concern than tone.

[somegeezer]

In my head, I use the "woofer/master", which I believe is the power amp attenuator. Plus it doesn't directly change my stage volume by upping the PA with it. Just my cabs.

[Bob Lee (QSC)]

Have the strongest possible signal all the way from the instrument, through the preamp and effects, to the power amp input, without clipping anything. In the power amp, use only as much gain as you need. Then your rig will be optimized for the best possible signal-to-noise ratio.

Fortunately, you typically don't need to be that rigorous about wringing out every possible dB of S/N ratio, though. You'll typically want some headroom remaining so that if you need to dig in, you can do so without any of the active stages running out of voltage.

[Oobly]

Thank you! That clears it up nicely for me. I will leave a little headroom at the preamp stage and control the final volume with the power amp dial.