Thanks for your link, this (a few paragraphs from the top) seems to settle it:

  Stan Ulam paraphrased John von Neumann as saying:

  One conversation centered on the ever-accelerating progress of technology and changes in the mode of human life, which gives the appearance of approaching some essential singularity in the history of the race beyond which human affairs, as we know them, could not continue.

   Von Neumann even uses the term singularity, though it appears he is thinking of normal progress, not the creation of superhuman intellect.

So the concept of technological singularly precedes and is independent of that of intelligence explosion- although one could argue that the latter is the most logical way for the singularity to come about.