I would talk to to Audio Research, technical support. They are great. Personally I always replace with exact duplicate tubes… but that is me. I cherish the Audio Research sound and simply wish to perfectly maintain it. But, that is me.
Re-tubing my Audio Research Ref 110
After taking advice here I've ordered 8 matched KT120 valves and 4 6H30 (getting difficult to get as can't import from Russia now!)
I've read the ARC instructions but want to make sure I've understood correctly - don't want to blow it (or me) up.
I turn it on for 15-20 with the speakers connected but no signal going through (so disconnect the source or mute?)
The I attach the multimeter, one to the yellow and one to the black beside each pair of tubes/valves. Does it matter which wire goes to which?
Then I turn the blue screw (guess the one adjacent to each set of the two tubes is the one?) The manual says I need to adjust to get 0.65V DC on the meter but that's for the original spec 6550 tubes. Is it the same for KT120 tubes?
And do I just stick the other 4 x 6H30 tubes in - do they need anything?