ARC Ref 3 bad tube?


I recently have developed a nasty sounding sporadic crackling sound in my system. It only happens once during each listening session. The crackling also comes out of both speakers in stereo. I have an ARC Ref 3 preamp and an Arc Ref 110 amp. I believe I have a bad tube but would like some opinions to make sure. I had my amp serviced in September 2009 by Arc so I don't think there is a problem there. The tubes in the amp have 1300 hours on them. The Ref 3 has 2500 hours on it. I replaced the four rear tubes at 850 hours with 6h30p-dr super tubes. The 6h30p tube under the 6550c power tube is orginal however. I replaced the 6550c tube in the preamp at 2200 hours. This is what I think is possibly wrong.
1.) The original 6h30p tube could be bad since it must get pretty hot from the 6550c tube above it.
2.) I noticed the 6550c tube has a strange looking white residue sticking to the inside of the glass. It almost looks like fine particles resembling styrofoam. That doesn't seem right to me.
I think it would be one of these two tubes since I get the bad crackling sound in stereo and not just one channel.

Thanks in advance for any advice.
tlg

Showing 1 response by cmalak

tlg...i suspect it's your 6550c tube that's the issue. I opened my Ref 3 and there was no such residue in my 6550c tube. It was all clear inside. By the way, why did you replace the 6550 at 2200 hrs in the Ref 3? ARC suggests replacing the 6550s in their power amps at 1500-2000 hrs but the 6550 in the preamp should be working a lot less hard so should last a lot longer (5000 hrs+) like the 6H30s in the Ref 3. Just curious. By the way, call ARC and ask for Leonard and describe what's going on. They should be able to guide you properly. Otherwise, if you bought your ARC equipment from an authorized dealer, they should be able to diagnose the problem or at least get on the phone with ARC and get their help in diagnosing it. Good luck.