Help me to drop 250vdc to 12vdc in a tube amplifier

[thebadtall]

hello, I would like to drop the voltage from 250vdc of a tube amplifier to 12vdc so that i can use a regulator to drop the voltage to 6.3 to feed 6 tube's filaments, wich total current is less than 6A i guess

i know i can use a cheap smps 12vdc psu with $1 from ebay for thiz task, but I dont want that.

can I achieve this with a 5w x? ohm resistor?

 

[tpetar]

Re: drop 250vdc to 12vdc

Something need to dissipate that difference if you whant to go transformeless or with resistors.

You can see high voltage voltage regulator switching/linear.

Best way is transformer, specially if you whant playing with electronic tubes.

 

[thebadtall]

Re: drop 250vdc to 12vdc

i have spare transformers, its no problem for me to use them. however,
i need 0.6a for 2x 6j8 tubes , 1.8A for 6L6 and 1.2A for 12ax7 total 3.6a plus a little bit for regulation lets say 4.5a /6.3 v is around 2.2a@12v?

i want to use a resistor in end, and i am asking if it will work constantly.. otherwise no problem, i plug the 12v transformer and lm317

 

[tpetar]

Re: drop 250vdc to 12vdc

Voltage is ok and that is possible, but that amperage this makes hard job for transformeless design.

 

[strabush]

Re: drop 250vdc to 12vdc

I don't believe the 250Vdc rail of the amplifier can source 6A. The best solution is to use a separate transformer.

 

[thebadtall]

i know its hard to do, i mean 6A @ 6v . i know that i will end up in transformer, but i am just asking...

 

[tpetar]

Did you try transformeless triac solution what I give you in other thread?

 

[thebadtall]

dead tpetar I left for urgent vacations!
(i took soldering iron along, and wife will divorse me)
you will understand when I return from my posts

 

[tpetar]

dead tpetar I left for urgent vacations!
(i took soldering iron along, and wife will divorse me)
you will understand when I return from my posts

:-?

Immediately throw soldering iron away, and save your marriage. We can alway buy finished cheap electronic device.

Go to buy some bouquet of flowers. :smile: