If you’d rather not open your C64 or 128, and have an expansion port free, we also offer an external cartridge option: The SID Symphony II. Designed to be as simple to use as possible, this cartridge is built for a 6581 SID, and works with any software that can access a SID chip anywhere in the $DE00 to $DFE0 address range (the address can be changed by moving a few simple DIP switches). Sized to fit standard Commodore 64/128 case shells (such as those sold by Protovision or Vesalia Online).