A LM317 needs a couple of volts higher input than output (and a heat sink for sure, but you can get it dead on by adjusting the two resistors.) Plenty of information on the web.
The fix you have is probably just as good as any. It's reversable, and therefore will not detract from the original value of the item.
You could also use a small bucking transformer on the primary winding in the eliminator.
:This eliminator works very well restored, but the "A" voltage is running a little high. Currently, I added a 3 ohm resistor to the original 3 ohm tapped resistor to drop the voltage a bit. Given the low rectified input voltage would a voltage regulator (e.g. LM 317)work effectively in one of these?
:
You can read up on LM317 here:
http://www.national.com/JS/searchDocument.do?textfield=lm317T&x=30&y=19
Probably not necessary but this regulator will give constant voltage out. Very easy to use with only 3 connections.
Norm
:The A voltage is running a little higher because the line voltage is probably at least 10 volts above what it was when the eliminator was built.
:
:A LM317 needs a couple of volts higher input than output (and a heat sink for sure, but you can get it dead on by adjusting the two resistors.) Plenty of information on the web.
:
:The fix you have is probably just as good as any. It's reversable, and therefore will not detract from the original value of the item.
:
:You could also use a small bucking transformer on the primary winding in the eliminator.
:
::This eliminator works very well restored, but the "A" voltage is running a little high. Currently, I added a 3 ohm resistor to the original 3 ohm tapped resistor to drop the voltage a bit. Given the low rectified input voltage would a voltage regulator (e.g. LM 317)work effectively in one of these?
::
:
:Hi Brian
:
: You can read up on LM317 here:
:
:http://www.national.com/JS/searchDocument.do?textfield=lm317T&x=30&y=19
:
: Probably not necessary but this regulator will give constant voltage out. Very easy to use with only 3 connections.
:
:Norm
:
::The A voltage is running a little higher because the line voltage is probably at least 10 volts above what it was when the eliminator was built.
::
::A LM317 needs a couple of volts higher input than output (and a heat sink for sure, but you can get it dead on by adjusting the two resistors.) Plenty of information on the web.
::
::The fix you have is probably just as good as any. It's reversable, and therefore will not detract from the original value of the item.
::
::You could also use a small bucking transformer on the primary winding in the eliminator.
::
:::This eliminator works very well restored, but the "A" voltage is running a little high. Currently, I added a 3 ohm resistor to the original 3 ohm tapped resistor to drop the voltage a bit. Given the low rectified input voltage would a voltage regulator (e.g. LM 317)work effectively in one of these?
:::
::
:
Primary and secondary current will be different. If a transformer was 100% efficient primary and secondary wattage would be the same.
Filament of a 5Y3 draws 2 amps at 5 volts. That's 10 watts. (5 X 2 = 10 watts) On the primary side current would be .083 amps to give the same 10 watts. 120 X .083 = 10 watts.
Norm
:
:Would the AC current draw be the full 2 amps as listed for the 5Y3GT filament? I tried an "in series" circuit measurement and got nowhere near that amount. Mind you I measured going into the transfomter.
:
:
::Hi Brian
::
:: You can read up on LM317 here:
::
::http://www.national.com/JS/searchDocument.do?textfield=lm317T&x=30&y=19
::
:: Probably not necessary but this regulator will give constant voltage out. Very easy to use with only 3 connections.
::
::Norm
::
:::The A voltage is running a little higher because the line voltage is probably at least 10 volts above what it was when the eliminator was built.
:::
:::A LM317 needs a couple of volts higher input than output (and a heat sink for sure, but you can get it dead on by adjusting the two resistors.) Plenty of information on the web.
:::
:::The fix you have is probably just as good as any. It's reversable, and therefore will not detract from the original value of the item.
:::
:::You could also use a small bucking transformer on the primary winding in the eliminator.
:::
::::This eliminator works very well restored, but the "A" voltage is running a little high. Currently, I added a 3 ohm resistor to the original 3 ohm tapped resistor to drop the voltage a bit. Given the low rectified input voltage would a voltage regulator (e.g. LM 317)work effectively in one of these?
::::
:::
::
:
:Brian
:
: Primary and secondary current will be different. If a transformer was 100% efficient primary and secondary wattage would be the same.
:
: Filament of a 5Y3 draws 2 amps at 5 volts. That's 10 watts. (5 X 2 = 10 watts) On the primary side current would be .083 amps to give the same 10 watts. 120 X .083 = 10 watts.
:
:Norm
:
::
::Would the AC current draw be the full 2 amps as listed for the 5Y3GT filament? I tried an "in series" circuit measurement and got nowhere near that amount. Mind you I measured going into the transfomter.
::
::
:::Hi Brian
:::
::: You can read up on LM317 here:
:::
:::http://www.national.com/JS/searchDocument.do?textfield=lm317T&x=30&y=19
:::
::: Probably not necessary but this regulator will give constant voltage out. Very easy to use with only 3 connections.
:::
:::Norm
:::
::::The A voltage is running a little higher because the line voltage is probably at least 10 volts above what it was when the eliminator was built.
::::
::::A LM317 needs a couple of volts higher input than output (and a heat sink for sure, but you can get it dead on by adjusting the two resistors.) Plenty of information on the web.
::::
::::The fix you have is probably just as good as any. It's reversable, and therefore will not detract from the original value of the item.
::::
::::You could also use a small bucking transformer on the primary winding in the eliminator.
::::
:::::This eliminator works very well restored, but the "A" voltage is running a little high. Currently, I added a 3 ohm resistor to the original 3 ohm tapped resistor to drop the voltage a bit. Given the low rectified input voltage would a voltage regulator (e.g. LM 317)work effectively in one of these?
:::::
::::
:::
::
:
Provided there wasn't any other secondary load and a transformer could be 100 % efficient 120 ohms would be right. You wouldn't need 20 watt resistor. 10 volts X .083 amps = .83 watts. In this case 2 watt resistor would be large enough. Consider 5 watt wire wound.
No transformer is 100% efficient. Figure most will be 80% or less. Could reduce resistance to 75 or 100 ohms. Do you have any other secondary loads?
Norm
:Thanks Norm. I would like to use a dropping resistor on the primary side to drop line voltage from 120 to 110. Using ohms law, that would be approx. 120 ohms, 20 w resistor?
:
::Brian
::
:: Primary and secondary current will be different. If a transformer was 100% efficient primary and secondary wattage would be the same.
::
:: Filament of a 5Y3 draws 2 amps at 5 volts. That's 10 watts. (5 X 2 = 10 watts) On the primary side current would be .083 amps to give the same 10 watts. 120 X .083 = 10 watts.
::
::Norm
::
:::
:::Would the AC current draw be the full 2 amps as listed for the 5Y3GT filament? I tried an "in series" circuit measurement and got nowhere near that amount. Mind you I measured going into the transfomter.
:::
:::
::::Hi Brian
::::
:::: You can read up on LM317 here:
::::
::::http://www.national.com/JS/searchDocument.do?textfield=lm317T&x=30&y=19
::::
:::: Probably not necessary but this regulator will give constant voltage out. Very easy to use with only 3 connections.
::::
::::Norm
::::
:::::The A voltage is running a little higher because the line voltage is probably at least 10 volts above what it was when the eliminator was built.
:::::
:::::A LM317 needs a couple of volts higher input than output (and a heat sink for sure, but you can get it dead on by adjusting the two resistors.) Plenty of information on the web.
:::::
:::::The fix you have is probably just as good as any. It's reversable, and therefore will not detract from the original value of the item.
:::::
:::::You could also use a small bucking transformer on the primary winding in the eliminator.
:::::
::::::This eliminator works very well restored, but the "A" voltage is running a little high. Currently, I added a 3 ohm resistor to the original 3 ohm tapped resistor to drop the voltage a bit. Given the low rectified input voltage would a voltage regulator (e.g. LM 317)work effectively in one of these?
::::::
:::::
::::
:::
::
:
:Brian
:
: Provided there wasn't any other secondary load and a transformer could be 100 % efficient 120 ohms would be right. You wouldn't need 20 watt resistor. 10 volts X .083 amps = .83 watts. In this case 2 watt resistor would be large enough. Consider 5 watt wire wound.
:
: No transformer is 100% efficient. Figure most will be 80% or less. Could reduce resistance to 75 or 100 ohms. Do you have any other secondary loads?
:
:Norm
:
:
:
::Thanks Norm. I would like to use a dropping resistor on the primary side to drop line voltage from 120 to 110. Using ohms law, that would be approx. 120 ohms, 20 w resistor?
::
:::Brian
:::
::: Primary and secondary current will be different. If a transformer was 100% efficient primary and secondary wattage would be the same.
:::
::: Filament of a 5Y3 draws 2 amps at 5 volts. That's 10 watts. (5 X 2 = 10 watts) On the primary side current would be .083 amps to give the same 10 watts. 120 X .083 = 10 watts.
:::
:::Norm
:::
::::
::::Would the AC current draw be the full 2 amps as listed for the 5Y3GT filament? I tried an "in series" circuit measurement and got nowhere near that amount. Mind you I measured going into the transfomter.
::::
::::
:::::Hi Brian
:::::
::::: You can read up on LM317 here:
:::::
:::::http://www.national.com/JS/searchDocument.do?textfield=lm317T&x=30&y=19
:::::
::::: Probably not necessary but this regulator will give constant voltage out. Very easy to use with only 3 connections.
:::::
:::::Norm
:::::
::::::The A voltage is running a little higher because the line voltage is probably at least 10 volts above what it was when the eliminator was built.
::::::
::::::A LM317 needs a couple of volts higher input than output (and a heat sink for sure, but you can get it dead on by adjusting the two resistors.) Plenty of information on the web.
::::::
::::::The fix you have is probably just as good as any. It's reversable, and therefore will not detract from the original value of the item.
::::::
::::::You could also use a small bucking transformer on the primary winding in the eliminator.
::::::
:::::::This eliminator works very well restored, but the "A" voltage is running a little high. Currently, I added a 3 ohm resistor to the original 3 ohm tapped resistor to drop the voltage a bit. Given the low rectified input voltage would a voltage regulator (e.g. LM 317)work effectively in one of these?
:::::::
::::::
:::::
::::
:::
::
:
A dropping cap works well in series with tube filaments or other resistive circuit. Do not try this in series with a transformer. It will become a tuned circuit and voltage could double.
Norm
:A dropping capacitor can accomplish the same thing for AC power ckts without generating heat: http://www.vintage-radio.com/repair-restore-information/valve_dropper-calcs.html
: