RCA to XLR adaptor causing amp to shut down

@brubin 

My DAC has dual differential XLR outputs and RCA. My amp is single ended. The DAC sums the SE outputs using op amps. The balanced outputs sound better than the summed SE outputs. So I use a transformer based passive which also provides a higher 4.0 volts vs 2.0 volts output and without going through extra circuits for SE output.  

There are some XLR balanced circuits that need a load on the inverted "-" pin of the XLR connector.  If you do not have a load on this pin, the circuit may run hot.  This could be the cause of your amp shutdown problem.  The Cardas RCA-to-XLR adapater is NOT the proper solution here because these adapaters will either float the negative pin or shunt it to ground.

You really need a unbalanced-to-balanced transformer, such as the Jenson ISO-MAX.

All, thank you for your comments, however from some of them, it seem I didn’t make things clear.  The Luxman is an integrated amp with RCA pre outs, there are no balanced outputs.   The speakers sound better with the active bass units driven from the pre amp but only have XLR input, hence the need for RCA to XLR adaptor. 
 

As stated in my original question, I cut the connection between pins 1 & 3, effectively floating pin 3 leaving only pin 1 connected to the earth tag.  This stopped the amp cutting out but introduced significant hum. 
 

Hope this clarifies things. Thanks 

This is what you really need if you want to do it right:

https://www.ebay.com/itm/Jensen-Transformers-DM2-PO-2RX-Stereo-Line-Output-Hum-Noise-Eliminator-Isolator-/361662342911?_ul=IL

there are various places to buy it.

Alternative, you could get the Jensen SUB-2RX:

https://www.cs1.net/products/jensen_transformers/SUB-2XX.htm

It's geared more towards subwoofer type frequencies.  Just make sure you select the "RX" model (RCA in, XLR out).