unwind toroidal transformer

[tonitze]

Since that I can't get 2x22vac toroidal transformer anywhere locally for my NIGC, I'm thinking of getting 2x25vac and unwind it for 2x22vac like what Peter Daniel did. I read about that somewhere in one of the thread but how successful this procedure is. Are all toroidal winded the same way? I'm worried that the sec. windings are overlapping one another that unwinding are not possible for both sec. winding. Any idea on that.

thanks

toni

 

[carlmart]

Since that I can't get 2x22vac toroidal transformer anywhere locally for my NIGC, I'm thinking of getting 2x25vac and unwind it for 2x22vac like what Peter Daniel did. I read about that somewhere in one of the thread but how successful this procedure is.

The procedure should work fine... but why do you want to do that?

With 2 x 25vac you are quite within the chip capabilities and you will have even more power. Heat shouldn't be much more increased either.

Use the toroidal as it is, don't unwind it.


Carlos

 

[tonitze]

I heard that it's almost the optimal voltage for lm3875 being not too much not to low. I wasn't sure though. Thanks Carlos.

 

[Sherman]

I heard that it's almost the optimal voltage for lm3875 being not too much not to low. I wasn't sure though. Thanks Carlos.

You should be fine at +-35VDC. After rectification your 25VAC will be about 35VDC.

I have also heard that lower voltages may sound better at the expense of power. I have built three different PS to test with my GC. The first puts out 26VDC into load, the second is 31VDC into load, the third is 35VDC into load. They all sound great but the one that puts out 31VDC has higher amperage and that makes a difference especially in the low end with my amp.

 

[tonitze]

Sounds like the +-31vdc is more popular. Even Peter Daniel, if not mistaken uses 2x22vac 400va. Beside that, my elcheapo speaker is rated 6 ohms. That why if possible I would like to go for 2x22vac, Thanks.

Toni.