Other project started : PRR vari-mu

Hello,
I've to buy the psu transfo. Normally it's a 110-110/12-12 transfo, but in France primary will be 220v. Has someone a solution to replace the original transfo.
I'd like to find the audios transfo at a seller in Europe. it could be the same has said in this project or others (edcor, oep,....). Any idea ?
Thank you :wink:

You can either buy a 220/12-12 trafo or use the primary of the 110-110 in series. An advantage of using a 110-110 trafo is that you can include a 220v/110v switch.

There is something that I can't understand , in this picture :


after the secondary of the transfo, what are the two rectangular boxes.?

Well i guess those are rectifiers.

Flo

thank you infernal death, do you know wich rectifiers I have to buy?

lol....it's obvious..400V/2A.....bonne chance mon frere.

Merci 3nity, je ne connaisais pas de pont de diode sous cette forme.I know only the W02,W04... series

:wink:

hello,
Now It's ok for the rectifiers :wink:
What I'd like to understand is how it's possible to use a primary of the transfo as a secondary.how does it work?
Thank you :wink:

A transformer can be used forward or reverse...
The perfect transformer formula is :
U1 = input Voltage
U2 = output Voltage
N1 = Input turns number
N2 = ouput turns number
U2/U1=N2/N1

Of course, it's never like this. There's energy lost in the iron and heat. But the transformer can be reversed !

For the transfo question :
You need 12 V and 110 V outputs
So the transfo setup can be :
220/12 into 24/220
This should work to give you 12v between the 2 transfos and 110v on the second transfo's primary...

Look an GYRAF DIY tube schematics they're all done like this :wink:

If it's not clear enough try :
In french :
http://fr.wikipedia.org/wiki/Transformateur_électrique
In english :
http://en.wikipedia.org/wiki/Transformer

You need a center-tapped transformer. Do a search here, I had the same problem a few months ago!