2. amps-preamps
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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
riley804
628 posts
 
Would this problem be the same as this one (08-09-09 ) :

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1249856770
tlg OP
69 posts
 
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.
cyclonicman
693 posts
 
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.
scousepasty
106 posts
 
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.
chadnliz
3,736 posts
 
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.
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