Left: TripleOscillator, one sine wave, coarse tuning 0, 440 Hz
Right: ZynAddSubFX, one sine wave, coarse tuning 0 AFAIK, 220 Hz

Same root note, same note played as the image shows. Both do output the correct note 69 through MIDI out.

(For further evidence, this is how I had to compensate in OpulenZ: https://github.com/LMMS/lmms/blob/master/plugins/opl2/opl2instrument.cpp#L306 )