How to resistance couple an open AF transformer in your 1920’s radios.
Пікірлер: 12
@mikemount4411Ай бұрын
Thank you for this video. Great information! I have rewound several transformers but it is not my cup of tea.
@curlyzim1Ай бұрын
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
@chuck0mxАй бұрын
Very useful... Thanks
@johnwiltson3164Ай бұрын
cool
@RichardNickels-ot6iqАй бұрын
Cool Nice 🙂💯
@jimmurphy5355Ай бұрын
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?
@curlyzim1Ай бұрын
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.
@Enigma758Ай бұрын
How does this work? Can an entire transformer be replaced with a couple of resistors and caps?
@curlyzim1Ай бұрын
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.
@jimmurphy5355Ай бұрын
How many (ball park) turns are there on this kind of transformer? Is rewinding that onerous?
@curlyzim1Ай бұрын
Sorry I don’t know how many windings but it looks quite cumbersome. The early AF transformers usually had a 3:1 ratio.
@manitoba-op4jxАй бұрын
not something you're going to do in a day but it's possible