Audio Research Classic 60 & 120 owners

Many thanks for sharing your thoughts and advice.

I will check the tubes as suggested by Hifigeek1 and will also check the tubes are operating with a bais of .65mv as suggested by Smoffatt.

Hifigeek1 could be right regarding a faulty tube (despite the tubes are new with less than 100 hours usage). Next, I will check on the socket as suggested.

Last week, ARC technician did suggest I should swap the tubes from the working Amp to the Amp that I am having problem with the blown fuse. After swapping and if the fuse still blows, then I should try swapping the caps from the good amp to the bad amp. I hope this will narrow down the uncertainty of tubes or caps being faulty.

I will report back with my progress. Wish me luck and keep your suggestion coming!

Happy hunting!

I currently own a pair of 120; just wonder if the fans have to be constantly on, ie. the cage have to be on; how can you access or adjust the bias port which is located inside the cage?

Yes, the fans must be on in order to properly cool the tubes and the surrounding components.

Hey Hifigeek1, thank you for your reply!
So from your experience, please advise how to adjust the bias port as it is located inside the cage!?