Why can't you play regular 78rpm records on an Edison Diamond Disc phonograph?
Why is the earth 93 million from the sun?
Why is everyone so grumpy?
I can't answer the latter two questions, but I can answer the first one: for patent reasons.
Edison didn't have the patent rights to lateral cut 78rpm records. Even when the controlling patents began to expire, Edison never offered a 78rpm adapter, and Edison discouraged his dealers from selling 78rpm adapters because he believed it would diminish his record sales.
That's the reason 78rpm adapters are so scarce; it's because they were all aftermarket items.
There were a number of different companies that sold these adapters. I'm not sure who manufactured the one depicted here, but it is typical in design in that it is slotted to be capable of accepting a Victor reproducer.
I have equipped this adapter with a nice rebuilt Victrola No. 2 reproducer, the finest reproducer of its era. Now you can also get quality Victor sound out of your Edison machine.
The adapter is quite easy to install. Just twist the knurled securing ring at the small end of the horn and the reproducer will pop in and out.
We buy, sell, and repair antique phonographs and music boxes.
Pick-up and delivery possible in many parts of the midwest,south, and northeast.