using 211 output tube in cary cad-211 anniversary


I want to switch output tubes in my cary 211 anniversary amps form 845's to 211's. does anyone know what bias resistor changes have to be made to do this? Cary was not much help.

If you have the Anniversary Edition, there is no resistor change needed. Just crank up the bias trim pot (on the back) until you get 100 mA on the meter. On my 211's, I had to crack the trim pot all the way up before any bias current was evident.

I would recommend first turning the bias all the way down, then power off and swap the tubes, then power on and rebias.
Are all 845 tubes interchangable with 211's? How do they differ in sound?