Your journey with the MA240's is amazing, I have the "gaggle" of 6AS7G's but I'm happy with them, the MA-1's are good in their own way.
My existing current Technics has single ended connections into adapter cables going balanced into the MP-1 that's why the RFI issue, if the connection would be balanced yes definitely the problem will be gone and YES his units are cable insensitive, I went replacing cables and trying different ones and if you keep "true" balanced end to end the cable makes no difference, a home made Mogami with Neutrik connectors is good enough.
My existing current Technics has single ended connections into adapter cables going balanced into the MP-1 that's why the RFI issue, if the connection would be balanced yes definitely the problem will be gone and YES his units are cable insensitive, I went replacing cables and trying different ones and if you keep "true" balanced end to end the cable makes no difference, a home made Mogami with Neutrik connectors is good enough.