Steve Smolian is correct about the "z" on Victor 78s. The records have superior surfaces to pressings from previous periods. Much quieter, due to a different mix in the material used for pressings. Victor seems to have used it from about 1933 to some time in 1935, after which the material was degraded again - although not to the level that it had been in the "Orthophonic" period (pre-1933). Does any member have more specific details? "Z" pressings are sought-after by collectors for their superior surfaces and are relatively uncommon because they were issued during the bad times of the Depression, when record sales were down. Don Tait