Good luck my friend. I’m quite impressed I can’t imagine rewinding. I wouldn’t have the patience. Remember the values of the components are just a reference it’s not that critical. I’ve seen some values of 50K ohms in the plate primary circuit and 470K ohms in the grid secondary circuit. And ceramic disc caps from.005 to .01 uF. I’ve always used the values shown in the video. 100K, 2M ohms and.006uF. 73’s KA1VMW Mark
Any idea why transformer coupling was used in the first place? Were early tubes so expensive, or low gain, or both that it made sense to use an expensive transformer between stages instead of much smaller, cheaper, lighter resistors and capacitors?
Thanks for watching the video. There were RC coupled in the 20’s. But like you said the tubes of the time were less than 100mw of gain until the UX-112A. AF transformers stepped up the gain so only two 01A tubes were necessary. But for same gain two AF transformers. Keep In mind tubes were very expensive at that time. The 01A cost $5 in the 1920’s.
Thanks for watching. Yes you can remove the transformer and RC the whole the circuit with two resistors and a cap. But that’s overkill when you can use the good side of the transformer and use one resistor with a cap to coupling the primary to the secondary windings of the transformer. And keeping the original transformer and hiding the resistor and capacitor in the housing of the transformer the radio will still look original.
Thank you for this video. Great information! I have rewound several transformers but it is not my cup of tea.
Good luck my friend. I’m quite impressed I can’t imagine rewinding. I wouldn’t have the patience. Remember the values of the components are just a reference it’s not that critical. I’ve seen some values of 50K ohms in the plate primary circuit and 470K ohms in the grid secondary circuit. And ceramic disc caps from.005 to .01 uF. I’ve always used the values shown in the video. 100K, 2M ohms and.006uF.
73’s KA1VMW Mark
Cool Nice 🙂💯
Any idea why transformer coupling was used in the first place? Were early tubes so expensive, or low gain, or both that it made sense to use an expensive transformer between stages instead of much smaller, cheaper, lighter resistors and capacitors?
Thanks for watching the video. There were RC coupled in the 20’s. But like you said the tubes of the time were less than 100mw of gain until the UX-112A. AF transformers stepped up the gain so only two 01A tubes were necessary. But for same gain two AF transformers. Keep In mind tubes were very expensive at that time. The 01A cost $5 in the 1920’s.
How does this work? Can an entire transformer be replaced with a couple of resistors and caps?
Thanks for watching.
Yes you can remove the transformer and RC the whole the circuit with two resistors and a cap. But that’s overkill when you can use the good side of the transformer and use one resistor with a cap to coupling the primary to the secondary windings of the transformer. And keeping the original transformer and hiding the resistor and capacitor in the housing of the transformer the radio will still look original.
How many (ball park) turns are there on this kind of transformer?
Is rewinding that onerous?
Sorry I don’t know how many windings but it looks quite cumbersome. The early AF transformers usually had a 3:1 ratio.