05-18-2023, 04:59 AM
Chas - another question is about the article & calculations. The 6F6 tube date sheets indicates 7,000 ohms. Data for the 37-60 radio says an S-7 speaker with 1 ohm voice coil.
57:1 ratio for output transformer would equal 57 squared or 3,249:1 impedance ratio. A 1ohm speaker would present a load of 3,249. That doesn't match 6F6 tube's 7,000 ohms.
Looks like the voice coil should be 2 ohms, or the transformer would be 83.6: 1 turns. (Square root of 7,000).
Bryan
57:1 ratio for output transformer would equal 57 squared or 3,249:1 impedance ratio. A 1ohm speaker would present a load of 3,249. That doesn't match 6F6 tube's 7,000 ohms.
Looks like the voice coil should be 2 ohms, or the transformer would be 83.6: 1 turns. (Square root of 7,000).
Bryan