That is likely the case if using a cheap transformer. But how is a step up or down different than 1:1 transformer, if both are isolation units, shielded, and with balanced output? I believe some manufacturers claim EquiTech-like units are not necessary with their equipment, but I don't recall them saying such a unit will harm their performance.
BTW, trying this is cheaper than switching the preamp. If this doesn't work as expected, a change in preamp can be done anyway.
BTW, trying this is cheaper than switching the preamp. If this doesn't work as expected, a change in preamp can be done anyway.