Upgrading an icon. The ibanez ts9dx turbo tube screamer takes on the mammoth task of attempting to upgrade the tube screamer. Adding a fourth control is the main addition that controls overdrive mode. This allows you to choose from the classic ts9 hot and turbo modes. Mode adds a little more grit to the original ts9 which is an unaltered ts9 with no modifications. Hot provides more crunch and boosts the mids. Finally turbo gives a real bass boost to add a powerful low end response giving this device real versatility even among tube screamers. If you are after a tube screamer with increased versatility but with classic ts performance and reliability the ts9dx is the tube screamer for you. The main difference between the ts9dx and traditional ts9 is the additional mode control with each position aside from the ts9 setting adding low end increasing volume and actually decreasing distortion. This means it also functions well with basses thanks to the improved low end response. Then the critical difference between the ts9 and the original ts808 is the output section which was altered to give the ts9 a more modern feel. This makes the outputted sound brighter and slightly less rounded so its all down to personal preference