Audio Matiere used ecc88/6dj8 for line stage/level and ecc83/12ax7 for phono stage/level, plus other rectifier tubes and sometimes El84’s (?) in their preamplifiers.
The US importer of Audio Matiere seems to still be in business (selling other goods now) and you might try sending them an Email.
http://marigoaudio.com
As suggested put the old tubes back in to see if it still operates.
If the circuit was designed for ecc88/6dj8 and you ran an ecc83/12ax7 in it it should still hopefully be OK as you barely powered/heated the 12ax7, but I would suggest not doing it again.
PS: Do not put an ecc88/6dj8 into an ecc83/12ax7 position/socket as you would be supplying 12 volts to a 6 volt tube (if the ecc83/12ax7 is wired for 12 volts).
DeKay
The US importer of Audio Matiere seems to still be in business (selling other goods now) and you might try sending them an Email.
http://marigoaudio.com
As suggested put the old tubes back in to see if it still operates.
If the circuit was designed for ecc88/6dj8 and you ran an ecc83/12ax7 in it it should still hopefully be OK as you barely powered/heated the 12ax7, but I would suggest not doing it again.
PS: Do not put an ecc88/6dj8 into an ecc83/12ax7 position/socket as you would be supplying 12 volts to a 6 volt tube (if the ecc83/12ax7 is wired for 12 volts).
DeKay