Lundahl xfrms in Gyraf M/S processor, can some one verify hook up.

[substitute]

Hello,
I've had four Lundahl 1+1:1+1 transformers kicking around the bottom of drawer for years.  I'd like to make a M/S processor using the Gyraf layout. 

Here's the relevant docs...
http://groupdiy.com/index.php?topic=5002.0
http://www.lundahl.se/wp-content/uploads/datasheets/1517.pdf

Hook up seems pretty straight forward, my only question at the moment is what to do with pin 2 and 5.  Just leave em hanging?

 

[moamps]

Yes.

 

[gyraf]

I think the LL1517 has split up coil sections over two bobbins (one in each leg of a C-core) - making it hard to use for matrixing as "local" coil coupling is better that "other" coil coupling.

You will probably want to use "Splitter" type transformers in stead - those are apparently better coupling-balance - see e.g. http://www.lundahl.se/wp-content/uploads/datasheets/PSW_WhitePaper_Download_Chapter_2.pdf

LL1527 is one of the transformers that are recommended for the purpose

Note: This does NOT mean that the LL1517 won't work - just that you may have to think deeply about how you do it.

In general, Lundahl's input transformers work much better for matrixing than their low-Z outputs.

Jakob E.

 

[substitute]

Hmmm, interesting.  I think I need to tac together a test rig and run some audio through them.  So, what's the concern?  To me it looks like loss of frequency response from improper loads could be an issue.  Is that what you're seeing?