In a phono preamp I built, there is an upper-lower triode pair, similar to a White Cath. Follower. The upper cathode has 87 Vdc to ground. So I connected a voltage divider from the HV supply to float the heater supply up on 60 Vdc. Positive, to the heater Common. The odd thing is, when measuring from Heater (positive meter lead) to cathode (neg. lead), I get -27 Vdc. Negative ! Why? Should I simply float the +12.3v heater supply Positive instead of the Common? I'm puzzled here.