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...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.
No, the problem then was bad PRP resistors in the ARC Ref 110 amp. ARC used a different kind of resistor at one time and then switched to a different style. I sent the amp into them and they fixed that problem and gave it a full check up. That is why I state in my post that I don't think the amp is causing the problem. I talked to Leonard before this amp problem (I thought maybe the 6550c in the REF 3 was bad and causing that problem) and he told me the 6550c should last up until 3000 hrs. I saved the old one so maybe I will try using it again and see if the problem goes away. They warrant their tubes for only 90 days so I would be out $100 if my new 6550c tube was the problem.
No matter what, the white residue indicates this tube needs to be replaced. In a perfect world, a 6550 should last for 3,000 hours, but there is no guarantee that it will. Tubes sometimes fall way short of the expected life and that is why you will never get a retailer to guarantee his 6500 tube will last for 3,000 hours.
The power tube in my Ref 3 went pop at about 500 hrs., easy to diagnose, no power! I changed it for a NOS GE6550A that I had, with a v.near match marking and the noticeable improvement over the standard valve was in bass and a deeper soundstage. Worth trying if you can get a GE6550A with a close match.
I just had my Ref 3 retubed last week, got a bad tube on Left channel but AR sent a new one out and I bet its the main tube aswell. Try Vintage tubes in Michigan, I went with stock tubes for the Ref 3 but went with a 1958 NOS RCA tube for the Aesthetix Atlas amp and the change was huge so next go around I am gonna try different tubes for the Ref3.
Calvin and the manager of service recommended changing the 6550 in my REF5 every 2000hrs, if you wait until it fails, expect a large repair bill.
Also, having owned several tube gear in the past, I recommend paying the extra and getting them from ARC. They test each tube and warranty them. I also recommend always having a spare set of tubes on hand just in case. Also, they are now using 6550EH instead of C tubes because they think they sound better. When I have my REF5 upgraded to SE in May-June, I will have them retube including the EH tube. Happy Listening!
I agree on finding an ARC warranty repair station. I have seen residue in 6550's and the tube was fine. If it's only happening on one channel it's not the power supply. First just turn the amp on and leave the preamp off. That will tell you if it's the amp. My guess would be the preamp and you could have a bad tube in it. I don't remember if that preamp uses constant current sources as it could be that as well or a resistor could still have gotten noisy.
Sorry to be a little off topic,but If you replace the 6550 tube every 2000 hrs, what happens with the tube usage reader? Is that used just to measure the life of the 6h30 tubes? Also why does the audio research web page state that preamp tubes should last about 5,000 hrs? I have never used a tube product prior to my ref 5 and am still abit confused about tube life and the consequences of using a tube past its expected life.
Good point. Normally in say, a 610T amplifier, the timer is expressly for the output tubes and gets reset by the tech. after replacing the output tubes as you have to go inside the amp to do it. The regulator in the Ref3 does not need to be replaced every 2K hrs. unless there's an issue. It can be replaced every 5K hrs. with the small signal tubes.
A concern I found with my Ref3 was that the tubes would slowly work themselves out of their sockets due to gravity and vibration. Also the pins and sockets seemed to need to be cleaned every couple of months are so to ensure the best sound. A couple of times I thought I needed to retube the unit only to find that the tubes were not fully ensconced in their sockets and needed cleaning. Once I had tuned up the preamp it sounded as good as ever. I even compared this process with a brand new set of tubes and found after a good scrubbing and repositioning one couldn't tell one set from the other.
It sounds like many a tube had been put in and pulled out. It may be time to either replace your tube sockets, or have someone retention them. If they're prone to falling out, it's time. I try and tell people when you are pulling tubes out of their sockets do not rock the tube back and fourth or you open up the tube sockets. Instead, pull straight out. In the Ref3 you don't have a lot of room and I believe you have little constant current source transistors near the tube sockets. I make sure the power supply is discharged and place one hand over the tube while I pull straight out with the other hand. That way your hand is stopping the tube's momentum and you don't slam the top of the tube into the metal barrier.
I think this is common for Ref 3. Great sound but bad design. I did everything you suggested. Not new at this. Sold the unit and moved on from tubes. But I'm sure one of the reasons for the Ref 5 was to solve the gravity problem.
In mine opinion a white residue at the top of the tube mean it is no longer vacuum anymore the getter wil be gone then,you should replace it, and be carefull put it in again so nothing will crack.