I have an r core transformer laying around and have good luck using it with a full wave bridge. But now I'm looking into replacing the bridge with a tube rectifier (274b) here's a link to the transformer:
https://tubedepot.com/products/r-core-20-plus-watt-tube-project-power-transformer
I know I need a ct on sec. #1 and sec. #2 is there a way for me to add it into the circuit?
Any help would be great as I don't want to use the Hammond or a toroidal transformers.
https://tubedepot.com/products/r-core-20-plus-watt-tube-project-power-transformer
I know I need a ct on sec. #1 and sec. #2 is there a way for me to add it into the circuit?
Any help would be great as I don't want to use the Hammond or a toroidal transformers.
You do need a center tap for using two rectifiers per secondary. Without a center tap, you can use a full wave bridge by adding two more rectifier tubes.
The usual dual rectifier tubes have a common cathode, so you need two more separate tubes to connect their anodes instead of their cathodes for the second pair.
The filament winding normally uses silicon diodes, though.
http://www.hammondmfg.com/pdf/5c007.pdf
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the traffo you are eyeing has secondaries not suitable for your requirement...https://d1sjrnpi226dnf.cloudfront.net/spree/attached_files/tr-pw-879s.pdf?1382030398
while it is possible to use secondary #2,it is rated for 3A and the 274 needs just 2A, you will have to use a dropping resistor,about 1ohm/10 watts.... center tap is not possible...although you can put two 56 ohm resistors on either side of the filaments to mimic a center tap...
Avoid that transformer like the plague.
It was designed for 100V mains, you have nominal 120V which often reaches 127V
Normal design expects and stands +/- 10% ... which would mean 110V tops ... you can easily have 27% more.
Overvoltage beyond a certain point (which you will surpass) dramatically increases core saturation and loss, there's many threads on that.
It's irresponsible for Tube Depot to sell them and shrug off "you can use them with no problems"
Even the 6.3V filament voltage is wrong by a lot ... 7.6 V AC .
Don't be blinded by the apparent low cost.
It was designed for 100V mains, you have nominal 120V which often reaches 127V
Normal design expects and stands +/- 10% ... which would mean 110V tops ... you can easily have 27% more.
Overvoltage beyond a certain point (which you will surpass) dramatically increases core saturation and loss, there's many threads on that.
It's irresponsible for Tube Depot to sell them and shrug off "you can use them with no problems"
Even the 6.3V filament voltage is wrong by a lot ... 7.6 V AC .
Don't be blinded by the apparent low cost.
Well made transformers supply rated voltage at the rated current.
So I can trust that originally expensive, well made transformer, to supply 6.3V with 3A load with 100V primary.
So it will very probably supply more than 6.3V unloaded ... with a 100V primary.
Which with a wrong primary voltage will rise even more.
To count with/need load to drop a filament voltage 20% below normal full load value, implies a grossly overloaded secondary.
How much?
4A? ... 5A? .... more?
To put it kindly, not good practice.
So I can trust that originally expensive, well made transformer, to supply 6.3V with 3A load with 100V primary.
So it will very probably supply more than 6.3V unloaded ... with a 100V primary.
Which with a wrong primary voltage will rise even more.
To count with/need load to drop a filament voltage 20% below normal full load value, implies a grossly overloaded secondary.
How much?
4A? ... 5A? .... more?
To put it kindly, not good practice.
of course, but in order to do that, these traffos have to start at a higher voltage when no load is connected...it is called "regulation"....
you are correct....
but here....https://d1sjrnpi226dnf.cloudfront.net/spree/attached_files/tr-pw-879s.pdf?1382030398 there is an intended application mentioned...
if it were just me i would have done it differently....
Confused here where does it state it's only for 100v use?
https://tubedepot.com/products/r-core-20-plus-watt-tube-project-power-transformer looks like 120v to me.
Anyways, I only used the high voltage line and I used a separate 5v 2a ct. for the filament seems to be just fine.
Now here's another question I'm using glasswares on/off switch
http://glass-ware.stores.yahoo.net/acswitch.html
I have the filament on position 1 and the Hv on position 2 when turning it on position 1 no problem but when turning it on to position 2 I get a loud pop also when turning off. Now you do need to know that my filament is using the ct for b+ so how do I get rid of this noise? Because the filament gets turned on and the ct supplies small amounts of voltage to the power supply then we turn on the Hv. Thoughts?
https://tubedepot.com/products/r-core-20-plus-watt-tube-project-power-transformer looks like 120v to me.
Anyways, I only used the high voltage line and I used a separate 5v 2a ct. for the filament seems to be just fine.
Now here's another question I'm using glasswares on/off switch
http://glass-ware.stores.yahoo.net/acswitch.html
I have the filament on position 1 and the Hv on position 2 when turning it on position 1 no problem but when turning it on to position 2 I get a loud pop also when turning off. Now you do need to know that my filament is using the ct for b+ so how do I get rid of this noise? Because the filament gets turned on and the ct supplies small amounts of voltage to the power supply then we turn on the Hv. Thoughts?
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