Sony Esprit audio Module replacement part

I made these boards to replace the Sony encapsulated Audio Module on TA-E901 Esproit series preamplifer These modules are not relaible many timeds they becomes very noisy whith scrath e scrash,.. The sources of the design are the schematic on service manual and some other Sony preampuifer from 70's to 90's. very important is the bias current becouse of complex power supply, it is made by a series fixed curent source and a shunt voltage regulator. BJT selection is very difficult, I choose the best PTH components on online catalogues, first JFET used for first differential is a Thoshiba smd component, the original 2SK244 quad fet is not available. Second stage is a differential BJT whith mirror current the are the push pull out class A biased whith correct current.