Audio Research D-90

Did you rebias them. If you move tubes around you must rebias. I had 2 of these at one time, I took tubes out and put them beck in I still checked bias even if they went back in the same spot. The D90 sounds great but is very fussy. I biased mine every month or so. I also did a hail mary when I turned them on. Very touchy equipment. I agree with Newbe also you could just have a bad tube, Move them around but again bias very time you move them. Do not swap 12ax7 with 12au7 as this can mess thing up alot. only use the tube recommended for that location, ARC's from that era again are very touchy.

Newbee,Hevac1,
Thank you for the info. I'm new to the tube world and don't know sh-t. I also have a C.J.,but biasing it is a breeze. The person I bought the A.R. from didn't send a owners manual and I don't know how to bias the amp or the tubes. So thats probably the problem. If one or both of you wouldn't mind taking the time,I'd really like to know. I've seen the meters for sell on Ebay,from China but didn't know if that was the answer.Thanks,Bill

You need a meter that does A/C & DC voltage. Most any will work ever radio shack one. I think you can go to ARC's web site and either download or request the manual.

Hevac1,
Thanks for the help.I have the volt meter but I don't know witch socket holes to check,what the reading should be or how to ajust the bias if it need be.Thanks again,Bill

I am still looking for the info for you.
I should have it by the weekend.