Input trasformer for lm3886
 

I wanted to ask you a suggestion on the connection scheme more suitable to use this (Lundahl LL1545A) as a line input transformer.
I attach the pdf transformer.

Thanks to all

Use it as a bal to unbal at the input to the 3886.
I'd suggest you use 1:1 for the 10k:10k impedances and load the output with the recommended components.

If your source is not balanced then keep your transformers on the shelf.

The L1545A can of course be used with unbalanced source, it will make ground loops a non-issue and will also provide blocking action for radio frequencies and it will be low noise as well. Source should have no DC, in doubt a series capacitor should be used (the amorphous core is well suited for AC coupling). Further, the 2:1 and 4:1 options can help use high input signal levels.

Thank you for your replies.
I wanted to be more accurate to say that I wanted to use it to connect 2 boards (3 x LM3886 in parallel) in bridge.
As is well set the output connections in this case?
I also wanted to take advantage of the transformer so that it can accept both balanced and unbalanced input.
it is good to go through a switch between balanced and unbalanced input?
Or not necessary?

Thanks to all

Feeding two amps for bridging is very easy as well, just use the L2B or L4B config.

A switch for bal/unbal input is not really necessary. I'd use a XLR + 1/4" TRS combo jack (Neutrik) and connect the xformer input for standard balanced. For unbalanced feed, use a RCA to 1/4" adapter, this autmatically shorts pins 1 (GND) and 3 (cold) of the XLR.

Thanks for the suggestion.
But i would install in my amply both types of connectors.
So in this case, i'm note sure if it's necessary a switch or just simply connect together pin2 of the xlr with the cold pin of the rca, and of course connect together the GND of 2 connenctors.