The Mellotron is really more of a sound transformer. The playback system is so analog and wonky you get a kind of warbly soft focus evocation of the original so

The Mellotron is really more of a sound transformer. The playback system is so analog and wonky you get a kind of warbly soft focus evocation of the original sound with a surreal, often epic, edge around it. Musically it's not at all a straight copy. Which is why it was so popular for prog, especially during its drug-enhanced heyday. The magic isn't in the reproduction, it's in the unique atmosphere it creates.