It's not really the piano he used. It is.....but it isn't.
Toward the end of his life, he had to have it rebuilt because it just simply needed it. The technician Steinway assigned to the job was not able to retain the piano's original attributes, and when Gould got it back, he was devastated. He said his own piano was now a stranger to him. He never forgave Steinway, and played Yamahas for the short remainder of his life. His last recording of the Goldbergs was on a Yamaha. This is written about in Franz Mohr's book, "my life with the great pianists."