Sorry to open this again, but this might be useful to some people. Going to numpy and then back to tensor might not be a good idea, especially if the tensor is placed on the GPU. Assuming the tuple is called xx, here’s how I did it when I bumped into it today:
xx  = torch.stack(list(xx), dim=0)

Writing this as a function:
def tuple_of_tensors_to_tensor(tuple_of_tensors):
    return  torch.stack(list(tuple_of_tensors), dim=0)