this is one of the transformers i got
ive very briefly tried with soekris and resistor i/v 4 stack tda1387 both pre buffer
although i think there are positives it seemed to suck a lot of energy out of the sound
also seems to be lower volume too which has to be considered too
ill have to put them between buffer and amp i think.....
with the soekris i also feed signal direct into the buffer bypassing the vol trim pot, was very lively and coherent
ill have to experiment some more with that pot