05-01-2022, 10:39 PM
While researching hi main volts and remedies, i had tried putting 3, 10 watt, 30ohm wire wound resistors in parallel in the line cord, I figured that my set uses
1.15 amp and trying to get a 10 volts drop i would use about 11 watts...so i thought my approximately 3x safety factor was enough.
The resistors hit 300 degrees after 15 min... maybe within derated values but still. Dang. More research and i decided to try and make a bucking transformer
out of a wall wart. It brought my voltage to around 110 now. Much less heat.
So to my problem, i have read using the heater voltage is a good guide of mains voltage to use. I measured the 6j5g AVC tube originally and went from 7.0 to about 6.5 volts . Much better until i started measuring random others and they are all about 5.8 volts now. I put in a nos 6j5g and the heater is the same about .7
above the others.
Why is one higher than all the others? I know there is a magnetic tuning transformer and maybe this is part of that, but the tubes around it the 6h6g and the 6k7g are also at the lower voltage.
Any ideas?
Thanks
Bill
1.15 amp and trying to get a 10 volts drop i would use about 11 watts...so i thought my approximately 3x safety factor was enough.
The resistors hit 300 degrees after 15 min... maybe within derated values but still. Dang. More research and i decided to try and make a bucking transformer
out of a wall wart. It brought my voltage to around 110 now. Much less heat.
So to my problem, i have read using the heater voltage is a good guide of mains voltage to use. I measured the 6j5g AVC tube originally and went from 7.0 to about 6.5 volts . Much better until i started measuring random others and they are all about 5.8 volts now. I put in a nos 6j5g and the heater is the same about .7
above the others.
Why is one higher than all the others? I know there is a magnetic tuning transformer and maybe this is part of that, but the tubes around it the 6h6g and the 6k7g are also at the lower voltage.
Any ideas?
Thanks
Bill