Pro Tracker v1.xx module
From Just Solve the File Format Problem
.pt1 files are modules produced by Pro Tracker v1.xx for the ZX Spectrum (not to be confused with .mod files produced by Protracker for the Commodore Amiga).
- SpeccyWiki - Pro Tracker (russian)
-  -- disassembled code of original Pro Tracker v1.xx module player (RAR archive)
- AYEmul (Cross-platform, source available)
- AYFly (Cross-platform, open source)
- zxtune (Cross-platform, open source)