In the past I did a thread on a French forum where you can find lots of information about JBL UREI 5235, including values and frequency responses for JBL 4350 dedicated boards.
https://www.jbl-vintage.com/t3066-fi...bl-urei-5235Be carefull if replacing 5532 op amp as power supply voltage can be above common tolerances of most of the op amps. In JBL UREI 5235 they can be replaced by LME49860, but also by very modern op amps like OPA1612 or OPA1656 (can be found already mounted on smd/dip adaptor). Low noise linear voltage regulators such as sigma78/sigma79 from amb lab is also an improvement.