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Philco Model 37-38B Questions
jjfritz5528
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Posts: 41
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City: Lancaster State, Province, Country: PA
#6

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?
Thanks
John N3MUN
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Messages In This Thread
Philco Model 37-38B Questions - by jjfritz5528 - 10-14-2023, 11:32 AM
RE: Philco Model 37-38B Questions - by morzh - 10-14-2023, 12:33 PM
RE: Philco Model 37-38B Questions - by radiorich - 10-14-2023, 12:49 PM
RE: Philco Model 37-38B Questions - by morzh - 10-14-2023, 02:51 PM
RE: Philco Model 37-38B Questions - by jjfritz5528 - 10-19-2023, 03:25 PM
RE: Philco Model 37-38B Questions - by morzh - 10-19-2023, 07:31 PM



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