RCA to XLR adaptor causing amp to shut down

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.