Installed new cart......taming the hiss......

Yesterday an audio bud re-installed my Dtna 20L and we set the Musical Surroundings Phonomena stage aswell.With my old MM AT cart I had a slight hum, like a bad ground but not bad enough to worry about but now I have a hiss I want to get rid of, its set at 60db gain and 304Ohm I think. What should I adjust and to what value to tame this down, I think it may drop back if gain is lowered but then the CDP volume will be far higher causing potential brainfarts to damge speakers when switching back and forth, Thanks for any ideas Chad