Exposure Vii pre-amp hum on mc input

[peelaaa]

Hi, when selecting mc on this pre-amp there is a low frequency hum coming from speakers. When selecting other inputs there is no hum, what could it be?

I'm using an ortofon mc25e cartridge and ar eb101 turntable

thanks

[Andrew B]

My first thoughts are "what's it sitting beside?" MC stages sometimes pick up hum like velvet attracts fluff. I had a similar problem when siting a DAC near my preamp

[potatoha]

I would check the tonearm grounding wire first. Is your tonearm grounding wire connected to the ground / earth terminal on the preamp?