• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

6v transformer


Does .3 volts really make that much of a difference?

How about a dropping resistor on the 6.3v transformer?

T23
 
You could easily drop this .3 volts in the secondary wiring to the filament without adding any actual resistors of precision value. Consider wrapping a small filament choke to drop this voltage.
 
  • Like
Reactions: 1 person
According to the data sheet for the 4CX250B, the cathode voltage is specified as 6.0 volts +/- 10%. That makes the upper limit 6.6 volts, so a 6.3v transformer will work just fine. Just make sure to check the transformer voltage under load to be certain it falls between 5.4 and 6.6 volts

- 399
 
  • Like
Reactions: 2 people
Yup. I think I'll just use a small dropping resistor to drop the voltage .3V. Just thought someone would know so I asked here. Yeah it could be run at 6.3V, but would have preferred to have had proper transformer. Oh well .3V @ 2.6A. Aint bad. Just a tiny resistor is needed and a small wattage rating. No biggie.
 
Yup. I think I'll just use a small dropping resistor to drop the voltage .3V. Just thought someone would know so I asked here. Yeah it could be run at 6.3V, but would have preferred to have had proper transformer. Oh well .3V @ 2.6A. Aint bad. Just a tiny resistor is needed and a small wattage rating. No biggie.

Crusher, searching for a needle in a haystack on this one.

Connect up the filament tr, see what it reads under load. 6.3 will probably be more like 6.1v.

Also the electrical mains are going to fluctuate depending on the hour of the day you use the amp.

Day time the mains can be as much as 5 to 7vac lower than at say 2am in the morning due to demand on the grid.
 
  • Like
Reactions: 1 person
I have one more question while I am asking. If I use one of the 12.6v transformers, and just use half the transformer, does that mean it is only half the rated amperage? Say its rated at 12.6V ct. @ 3A. Should I go to 6A so I have 3A on that side? I'm new to tetrodes and just starting out with a 250B. In the past I have used triodes and used the proper filament transformer. I'm still learning on the tetrodes. Not all the way there yet.
 
Thanks guys, pretty much got it done. picked up a 4A transformer. just used 1/2 of transformer. ended up using a .2ohm, 5W resistor to drop voltage down to 6.05V. It was sitting at 6.5V. Thank you everyone that helped out.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated