Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_73777 ( "Driver Unit Model No." text, "Release Year" real, "Output Voltage (RMS)" text, "Inputs" text, "Outputs" text, "Notes" text )

### Question ###
What year were outputs is 2x pro bias, rca loop out and notes is vacuum tube released?

### Accurate SQL ###

SELECT "Release Year" FROM table_73777 WHERE "Outputs" = '2x Pro Bias, RCA Loop Out' AND "Notes" = 'Vacuum tube'