27-09-2018, 05:42 PM
I've found a transformer from a Bush with almost the right size "E" and "I" laminations, its very small at 42mm X 35mm. This is from an AC11 which uses an UL41 output valve. It has an open circuit primary, very common to fail this way.
The stack size needs to be 13mm maximum. To get it into the existing frame I will need to grind nearly a millimetre off the end.
The problem will be getting enough copper into the small window, 21mm X 7mm with the necessary bobbin.
The bobbin will have to have end cheeks as I cannot wind without.
As the quoted anode current is 21.5 mA minimum the primary wire gauge will be problematical.
The ratio works out at 41.6 to 1 taking the ra as 5200 ohms and the speaker at 3 ohms.
I'll let Ed Dinning have the figures and see what he can come up with.
Sam.
The stack size needs to be 13mm maximum. To get it into the existing frame I will need to grind nearly a millimetre off the end.
The problem will be getting enough copper into the small window, 21mm X 7mm with the necessary bobbin.
The bobbin will have to have end cheeks as I cannot wind without.
As the quoted anode current is 21.5 mA minimum the primary wire gauge will be problematical.
The ratio works out at 41.6 to 1 taking the ra as 5200 ohms and the speaker at 3 ohms.
I'll let Ed Dinning have the figures and see what he can come up with.
Sam.
Boater Sam.
