A transformer is not a neccesity. There are all tube phono stages that can handle the job. I use an Aesthetix IO phono stage that is all tube with a .34 mV cartridge with wonderful results. I have also used a solid state Pass AlephOno that was very nice.
Low Output MC's- Are We Playing W/ Fire ??
Might the current rage w/ low output MC's and the neccesity to use step-up transformers, at least on tubed phono stages, be introducing a new potentially harmful link into the chain. Not all step-up transformers are created equal. Might we get overall better performance out of a well executed .45 mv output design ( Helikon ) w/o using a step-up vs. a .22 mv output ( Helikon SL ) w/ a step-up. Or are low outputs almost ALWAYS better ?