Bought by chance in Monacor to mirror the inputs of a powered speaker, I was very surprised by the quality of the correct transformer.
This is the one used in their passive DI, which are not bad at all.
I regularly used to tinker with double DI, a symmetrical power supply box AKG B29 or tinker Micro SD (yes, it works in reverse a transformer!). Very low price, sound quality quite satisfactory. I still have stock