This is a free guitar amp VST Plugin from Shattered Glass Audio called Ace. Finally we found a free VST amp for mac users. Make sure to try it out and let us know if you liked it.
Ace is a faithful digital emulation of a legendary 1950s, American, all tube, tweed, 5W amp. We have added to the model two of the most common amplifier mods: adjustment of the amount of feedback and addition of grid stopper resistors, both of which can be turned off for the original amp sound. For added flexibility, speaker emulation can be switched out in case you want to use a different speaker emulator. Ace also features 2x, 4x, or 8x selectable oversampling.
Simple controls and a conservative CPU usage make ACE easy to use in live settings as well as for re-amping.