As a collector of early recordings- 78s and cylinders are quite fragile. In my opinion it is quite possible that even 'many' MT recordings simply did not survive. I owned a very rare, expensive 1905 one-sided disc by Ossip G's friend Mark Hamburg, who also attended the Vienna dinner where O met Clara. It cracked one day as I picked it up with two hands. Early recordings were discarded when broken. They break even in protective albums. Cylinders decay. Empty cylinder boxes are common in antique stores. I have also never found any trace of Clara recordings, having visited the Berkeley, Hartford and Detroit archives. I would be very surprised that she never made home recordings, speaking as a vocal coach. In my extensive files on the Gabrilowitsch family, no hint of a Clara recording. gregm