If you play bass, you've probably heard for Ampeg - this historic brand that virtually invented bass amps. IK Multimedia's Ampeg SVX is a virtual collection of bass amps that bring you the signature sound found in the Ampeg hardware.
Aside from saving you a lot of money from buying the hardware, Ampeg also offers a great way to experiment with your sound. You can mix and match between amps and cabinets for a total of 24 different combinations. There is also a virtual pedalboard with 6 stomp effects.
Ampeg SVX is based on Amplitude, also from IK Multimedia, but was specifically designed to emulate the Ampeg sound. Since it runs as a VST, RTAS or AU plug-in, Ampeg will be useful for everyone, not just bass players. Even if you use a virtual bass (such as Virtual Bassist or Broomstick bass) running your signal through Ampeg SVX will make a big difference in adding that authentic bass sound to your mix.
Guitar
