Common wisdom says the transformer has to be balanced for any sonic benefits to accrue.
Sabai
no, this is NOT a true statement at all. A transformer can be benefitial even if it's single-ended. it just has to be designed correctly for the job that it is intended to do. In a balanced xformer by making the AC signal differential the architecture allows for rejection of common-mode in the topology itself. Whereas in a single-ended xformer you have to use mu-metal cans for shielding & reduction of capacitative coupling. Just 2 different ways to skin the cat....
what do you think - all the transformers used in solid-state audio are all balanced? Do you think that the EI transformers so widely used in tube equipment are all balanced? Do you think that all the wonderful super expensive, wonderful sounding MC step-up transformers are balanced? No, they are not.....
Yet their impact on the sonics is remarkable.