PS: I ask Daniel Coulom for a tool to convert .k7 to .wav format (tape). For the opposite way exist a tool.
Thanks goes to Yo_fr (the developer of the MESS driver) to send me a .wav files for testing. He made a tool to convert K7 to WAV format, maybe he can help to add in castool.
hector1 driver Game : Formule 1 (Tape)
hec2hr/hec2hrp/hec2hrx/hec2mx40/hec2mx80 driver Game : Stramble (High resolution, Tape)