i have a PWD II and PWT driving some Cary Mono Blocks and can’t seem to eliminate

hum coming from the speakers. i’ve lifted grounds (cheater adapter) but still have the hum.

powering up the amps without any input attached they are dead quiet.

once i attach the input the hum comes back.

i’ve lifted the grounds first on the amps. then lifted the dac/pwt with the grounds back on the amps. no luck.

its not bad but i would like to eliminate it if possible.

thanks for any suggestions!!