Isolation transformer

I used a Topaz isolation transformer for a few months but have since removed it. The reason is my incoming ac voltage fluctuates between 119 and 127 volts. The output of the topaz had a 2 v gain so when I would have 127v in I would get 129 out. Too high for my tube amp.

When it was in I had a slightly lower noise floor. The other factor I did not really care for was the parisitic power being used. What I mean is with NO LOAD it was very warm and I figured it was using about 90watts.

My Topaz is a 2.4KVA and I did not see any taps to adjust the voltage. BTW the Topaz Is a balanced output with a whopping -146db in common mode rejection (neutral to ground)(forget what normal mode was). I used a clamp on amp probe to measure the current then multiplied by the input voltage to get the 90w. Now my Topaz does have a slight hum (wish I could teach it the words intead).