Yes they are interchangeable - they all plug into a noval socket. 🤢
More seriously, your question can only be answered if you provide more context. In what circuit? E180CC has been successfully used to replace 12AT7 (ECC81) in some circuits. But it’s parameters are not close enough to either 12AX7 or 12AU7 to work optimally in either of those places. You might want to check the tube data sheets available online.
More seriously, your question can only be answered if you provide more context. In what circuit? E180CC has been successfully used to replace 12AT7 (ECC81) in some circuits. But it’s parameters are not close enough to either 12AX7 or 12AU7 to work optimally in either of those places. You might want to check the tube data sheets available online.
Sounds like a good plan. While they are not good in place of 12AX7 or 12AU7, they are very good in circuits designed for them. Some folks treasure them as lower mu 12AT7 substitutes and are willing to pay good prices. Good luck.
As an EL80CC never existed, the OP needs to specify whether he meant E180CC or E80CC.
Best regards!
Best regards!