The 6n11 has different heating current and is louder on HF than a ecc88. If you want to replace the tube in a 6n11 circuit, without dulling down the treble, then a probable is a 6n1p and not an ecc83.
G
Amperex "Bugle Boy" tube compatibility
I need to replace a vacuum tube in a pre-amp section of the integrated amplifier as the previous tube Beijing 6N11 went bad. The Amperex "Bugle Boy" ECC83/12AX7 tube has the same pin layout as Beijing 6N11 tube. According to description on Amazon the Beijing 6N11 may be used instead of ECC88, E88CC, 6922, 6DJ8, 6922 and 7308. Would it be okay to use Amperex "Bugle Boy" as a substitute to Beijing 6N11 tube?