5f1 transformers

[Mnvizb]

Hello everyone,

I have decided to build a 5f1 champ. This will be my first tube build and I really need some guidance. I have decided not to go with a kit because it's more rewarding and cheaper that way.

I understand the schematic, but I don't understand what transformers do I need? The good news is that my friend has huge stock of both power and output transformers for tubes. Could you please help me and give me parameters of both power and output transformers (Not models)? I am NOT going to use a tube rectifier!!!.

If you need any more information please post here.
Thank you

 

[Cassiel]

For the power transformer - the circuit needs around 340 DC volts (75mA) and 6.3 AC Volts (1A). The currents given are a minimum, it would be better if the transformer can handle extra current.

For the output transformer you need one with a gap in the core and big enough to handle at least 50 mA of DC current. Secondary between 5K to 8K (not critical).

 

[Mnvizb]

Thank you very much. But another queston arised. You wrote:

For the output transformer you need one with a gap in the core and big enough to handle at least 50 mA of DC current. Secondary between 5K to 8K (not critical).

What does the gap in the core? What is the difference? If i won't find one with a gap, can I use one without it?

Thank you again

 

[Cassiel]

To prevent core saturation. Sorry, a good explanation requires many words - just google air gap SE transformer.

I am NOT going to use a tube rectifier!!!.

Forgot to say that there are different ways to get 340 DC volts out of a transformer. This PDF document should help you to understand what I mean:

http://www.google.es/url?sa=t&rct=j...2LTdBw&usg=AFQjCNFPNgWFEfkADk5oUMa3KwjgqL3-YA

 

[ChrisA]

Thank you very much. But another queston arised. You wrote:



What does the gap in the core? What is the difference? If i won't find one with a gap, can I use one without it?

Thank you again

A single End amps has a lot of DC current flowing through the output transformer. This current would fully saturate the iron core. So they make the core less able to be magnetized by literally cutting a gap in the iron

Yes you can use a transformaer without this gap but you would then need an iron core that is MUCH larger, like twice or more the size (and cost) The air gap is make it more affordable

I just build a champ. The best transformers for use in a Champ clone are these: Fender Style Transformers
Just get the two with the lowesr price. Not the "upgrade" versions. But I always include chokes in my builds, get one of those too.

Buy them here: ClassicTone Transformers by Magnetic Components, Inc.