The attached data is from an old Amertran catalog. Bulletin 1002B, 1935.
In the left column,
wattages are shown. In the center
DB are shown as '+24', +'37'. etc..
These are basic 500 Ohm line to various secondary speaker or other line impedances.
I take it that the Wattages are the actual handling ability.
Because they specify Ohms-to- Ohms, I do not believe these are for 'constant voltage' line to speaker' service. Did those exist in 1935?
in my table below, the leftmost two columns are from the data sheet. The rightmost two are what the watts and dBm should be, if translated from the data sheet values. It does not match. I'm sure I am missing some very simple thing.
- application Wattage - | - Max. DB -but.. | - the Wattage is dBm - | - The DB are Watts - |
4.5 | +28 | 36.5 | 0.63 |
15 | +24 | 41.8 | 0.25 |
30 | +37 | 44.8 | 5.0 |
30 | +37 | 44.8 | 5.0 |
15 | +24 | 41.8 | 0.25 |
What is to be made of this? How has a 4.5W transformer more DB than a 15W transformer?