cleanup

[andrew]

Why do some amp designs retain clarity when the volume is turned down on the guitar and some loose clarity? Thanks for any insight.

[Tonegeek]

Why do some amp designs retain clarity when the volume is turned down on the guitar and some loose clarity? Thanks for any insight.

I wonder the same thing and I have some thoughts about that.

Some electronic devices including tubes are not linear. They don't amplify all frequencies the same throughout their operational range. Tubes don't all compress the same way either. My Marshall 18 watt breaks up and gets fatter sounding the more I turn it up. Turn the guitar volume down and it gets less distorted, less compressed and gives back some high end. Its a very useful feature of this amp. This amp is mostly distorting the output tubes (in this case).

My Dumble clone which is getting its distortion mostly from the preamp behaves much differently. It seems to gain a bit of high end when pushed. Also there are more stages of distortion. Backing off the guitar reduces distorting somewhat, but it also reduces the high end. This seems to be a characteristic of the pre-amp tubes. Since there is more stages of distortion, there is no way to guarantee multiple stages will clean up at the same time so you have to roll the volume back more on these amps than you would on the simpler amps that rely on power tube breakup. Still it doesnt clean up that well. Channel switching, and boost relays give you options to overcome this limitation and then some.

I am sure there is more to this discussion...