Decklink Studio, Mixer, Y cable?? PLEASE..

Firstly, I would like to express my gratitude to all the helpful people on this site, would never have got this thing going without the help and advice.. I thought I knew everything I had to know about wiring audio and video but QUICKLY realised, I know very little about balanced signals...

Basically with the help of another forum member I got good audio from channel one and two into my mixer... My Mixer.. It has two BALANCED Mono inputs that I am using for channel one and two.... the remaining inputs on my mixer are unbalanced. It is a Yamaha mixer... The remaining channels are Left Right Stereo BUT the LEFT only says Mono, so I assume you use just Left for Mono, ONLY PROBLEM is it is UNBALANCED.. So when I hooked up Channel 3 and 4 to the mixers Mono chanels 3 and 4 with Balanced TRS cable, I got nothing but LOUD distortion and crackling...

To my question? If I use a 6.5mm TRS(Stereo) cable to 2 x 6.5mm Mono Jacks (ie: Y Cable stereo to Mono) plug the stereo end to the decklink and the mono ends to the LEFT AND RIGHT of one of the mixer channels? will this eliminate the distortion and solve the problem???

Thanks in advance.
Tony.

Tony