10-19-2023, 03:25 PM
Additional questions related to the Output transformer. I purchased a Hammond #125A for Push-Pull output, 3W. The DC resistance is a fair amount lower than the original. 115/165 ohms vs. 320/350 ohms on the original.
I'm concerned that this would exceed the Plate Current rating of the 1J6 tube (50ma). Should I add a resistor to each leg to be similar in total DC resistance for each half of the winding (185/205 ohms)?
Not sure what the original impedance was for the Philco transformer, the Voice Coil is stated to be 5 ohms, so I will plan to use the 4 ohm output on the replacement. The Primary also has choices. The 1J6 states a 10k Plate-Plate effective resistance. The closest to that for the 4 ohm output is either 11.2k or 8.8k. So I'm thinking
11.2k would be safer.
Thoughts?
I'm concerned that this would exceed the Plate Current rating of the 1J6 tube (50ma). Should I add a resistor to each leg to be similar in total DC resistance for each half of the winding (185/205 ohms)?
Not sure what the original impedance was for the Philco transformer, the Voice Coil is stated to be 5 ohms, so I will plan to use the 4 ohm output on the replacement. The Primary also has choices. The 1J6 states a 10k Plate-Plate effective resistance. The closest to that for the 4 ohm output is either 11.2k or 8.8k. So I'm thinking
11.2k would be safer.
Thoughts?
Thanks
John N3MUN
