RCA to XLR adaptor causing amp to shut down

RCA to XLR adaptors are not good you will always loose sound quality.

Cardas makes an XLR to rca adapter that floats pin 3.  All the other adapters I have used tie 1 & 3 together which can short out some electronics. 

The more expensive way to do this is to use an isolation transformer. 

If your amp is not using the XLR pins in the proper configuration, I can see how this might happen.- That the Levinson works would seem to confirm this.

B

Just swap the hot/return between 2 & 3.

There is no absolute standard. I had to rewire my Shure mic transformers back in the day.

Another vote for Cardas XLR-RCA adapters, they worked flawlessly for me. 

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 

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).

Thanks Auxinput. As I’m in the UK the Jensen products work out costly with duties etc, so based on your advice I’ve ordered an Art DTI duel transformer isolator and it’s an easier return should it not work. If it cures the issue but impacts the sound quality I’ll probably go for the Jensen unit or get a custom built unit locally.  Thanks again

That ART DTI will likely work just fine.  It's an RCA-to-XLR transformer similar to the Jensen.  Like you said, if sound quality drops, the Jensen is likely to be better.