Anyone know what the real- world differences are ? The RCA rcving man. says the 12AZ7 is identical to the AT except for heater- cathode ratings, and interelectrode capacitances. The heater-cathode voltage ratings are higher on the AZ.
What I'm thinking of doing is replacing the chinese 12AT7 in this MXL 960 (chinese tube mic) (that doesn't sound half bad) with one of these 2 nice early 60's RCA 12AZ7s that I have laying around. So -- does anyone know what effect the differences in the interelectrode capacitances will have - if any??