Jay Mitchell
Fractal Fanatic
This may or may not turn out to be significant, but it's certainly interesting. In the Advanced settings in the amp block, there are three possible selections for the "Input Select" parameter. The three settings are "Sum L+R," "Right," and "Left," and the default is "Sum L+R." The default setting is presumably so the block will pass signal if you're using a right-channel input, but the front input feeds the left channel only.
Last week, just for grins, I changed the setting from the default to "Left" and got a surprise (which, in retrospect, should not have been a surprise). The gain increased, and the character of the sound was quite different. Now, since the amp block is nonlinear, the gain increase at its input produced several collateral tonal changes, as well as increasing the drive/saturation of the block, so what I was hearing was the result of multiple variables being changed together. Reducing the Drive parameter brought things back in line, but I think there is still a difference (which I prefer, BTW), due to the fact that the response of the amp block can vary with the setting of the Drive parameter.
Having thought about this some more, it dawned on me that it only makes sense to introduce attenuation at a summing block. Two uncorrelated signals of equal level, when added together, produce a summed signal that is 3dB higher in level than either signal alone. Attenuating the summed signal helps prevent output clipping in the Axe-Fx.
However, if you're not sending two signals through the amp block, there's no need to have this attenuation, and the added drive level may change things in a desirable way. I've changed the amp block input select parameter in all my presets to "Left" and adjusted the Drive parameter accordingly. If you're experiencing trouble getting enough drive with a given amp block, this may get you where you want to be without having to add a block just for some signal boost.
This is all FWIW. I'm not claiming to hear huge differences, but I'm pretty sure that there is a difference. If you're not feeding the amp block with two independent signals, it certainly won't hurt to select the left input.
Last week, just for grins, I changed the setting from the default to "Left" and got a surprise (which, in retrospect, should not have been a surprise). The gain increased, and the character of the sound was quite different. Now, since the amp block is nonlinear, the gain increase at its input produced several collateral tonal changes, as well as increasing the drive/saturation of the block, so what I was hearing was the result of multiple variables being changed together. Reducing the Drive parameter brought things back in line, but I think there is still a difference (which I prefer, BTW), due to the fact that the response of the amp block can vary with the setting of the Drive parameter.
Having thought about this some more, it dawned on me that it only makes sense to introduce attenuation at a summing block. Two uncorrelated signals of equal level, when added together, produce a summed signal that is 3dB higher in level than either signal alone. Attenuating the summed signal helps prevent output clipping in the Axe-Fx.
However, if you're not sending two signals through the amp block, there's no need to have this attenuation, and the added drive level may change things in a desirable way. I've changed the amp block input select parameter in all my presets to "Left" and adjusted the Drive parameter accordingly. If you're experiencing trouble getting enough drive with a given amp block, this may get you where you want to be without having to add a block just for some signal boost.
This is all FWIW. I'm not claiming to hear huge differences, but I'm pretty sure that there is a difference. If you're not feeding the amp block with two independent signals, it certainly won't hurt to select the left input.