Soundtracs Topaz 12 — 4 Manual

The Topaz usually uses an external power supply unit (PSU).

The stock internal PSU runs hot. If your 12-4 hums or has crackling channels, it's likely the PSU caps, not the channel strips. Many users externally mount the transformer or recap the PSU immediately. Soundtracs Topaz 12 4 Manual

The manual’s recommended gain structure is: aim for 0VU on the meters (which corresponds to +4dBu output). However, the Topaz actually sounds best when you drive the mic pre into the yellow (around +6 to +9 VU). Without the manual, use your DAW’s input meters: set channel fader to unity (0), adjust the trim so your loudest peaks hit -12dBFS in your DAW. That’s the sweet spot. The Topaz usually uses an external power supply unit (PSU)

Manuals.lib (manuals.lib) hosts a massive collection of vintage pro-audio manuals. Their Soundtracs folder includes the Topaz 12/4 Owner's Handbook. It is a scanned photocopy, slightly grainy on the schematics, but completely legible. Look for the file named Soundtracs_Topaz_12-4_Owners_Manual.pdf. Many users externally mount the transformer or recap

Unlike a Mackie 1604, which you can figure out in ten minutes with a drumstick and a beer, the Topaz is weird. It’s a split console design (like a big SSL) masquerading as a small project mixer.

Here is what the manual explains that common sense does not:

For the 12/4, this includes: