usb/spdif volume is too high

I'm having another usb/spdif problem after 9 years( first one was m2tech evo usb converter +8khz 3db roll off) one of me usb converters have unusualy high output level ( chineses brezze audio xmos u8) comapring to others usb/spdif converters which have also xmos u8 chip. without changing anything on analog setup its louder by 8db. i barely can adjust digital volume on pass labs xa200.5 to mark levinson dac's in foobar- it very loud from the very begining. i have checked all three outputs of that converter -spdif/ XKLR aesbu and optical- levels are the same(8 db louder than other converters) . i always thought that spdif format output level is standartized and fixed? 😕 any way to reduce output?