The "4" in "12-4" refers to the Groups. According to the manual, these are designed to simplify your mix.
The Topaz uses an external PSU. Ensure it has plenty of ventilation, as these can get warm during long sessions. Soundtracs Topaz 12 4 Manual
The Soundtracs Topaz 12-4 is more than just a mixer; it’s a piece of recording history. By mastering the routing and EQ sections outlined in the manual, you can bring a depth and character to your recordings that digital plugins often struggle to replicate. The "4" in "12-4" refers to the Groups