RCA to XLR adaptor causing amp to shut down


Can anyone help guide me please: Using RCA to XLR adaptor causes amp to shut down going into protection mode. The application is Luxman 595ASE pre out RCA to XLR on Avantgarde Duo Mezzo XD active base units.
When using Mark Levinson pre RCA out this works fine.

Opening up the adaptor, pins 1, 3 and what I assume is an earth tag are linked with pin 2 connected at the RCA end. I tried cutting the connection between pins 1 & 3 and this stopped the shut down but introduced a significant hum.

chrispb1

Balanced to Unbalanced, Why are you doing that for?   If you can support RCA to RCA do that or XLR to XLR.  Otherwise, XLR to RCA is a waste of money. on does not provide any value. 

@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