Boss GT-1000 core looks small, neat and very powerful. However, I like my digital effects separate and focussed and not all the "development put in one box". Which is why I like Source Audio gear so much. If I was dirt, I get an Aftershock or an Ultrawave. If I want an Octave or filter, then the Spectrum or C4. If I want a great multi mod, then the Luna is perfect. Helix for delays...Ventris for Reverbs. Most of these are best of breed. Unlike say a Helix or a Boss GT1000, where the quality of an effect is due to left over budget at the end of a long dev cycle with hit / miss results.
The Aftershock is more than capable of creating the Ampeg tones that you are looking for.
The Aftershock is more than capable of creating the Ampeg tones that you are looking for.