remember 30% tax at least
I graduated Electrical Engineer in 2006, USD 58k before tax, 40k after tax
Right now, my salary is USD 120k + bonus before tax.
75k is too less in CA, especially your son grad in Caltech.
California is double income tax, and the cost of living is the 2nd high in US
40% tax, 75*0.6 = 45k in your pocket
I recently hired two fresh graduate BSEE with 3.6GPA+ from UIUC, 80k starting salary