As I said, its almost identical to the Lately Bass, when I created the DX7 Version of the Lately Bass (back 2004) a friend sent me the FB01 sysex so I was able to compare it to the TX81z version. Simply change the Operator 5 waveform to sine and you have it, other than that you can try several other conversions from other sounddesigners like 4Op Bass and FB01 Bass,