DOA tube from Audio Research


I just opened a matched quad set of 6550 tubes I bought last year from ARC and one of them is DOA. How can this have happened? I thought they were the most highly screened and tested tubes available. Has anyone else ever had this happen? I immediately called their support line and got the support guys voice mail saying he is on vacation. This is really frustrating. I've been waiting until I had some spare time to listen at length to the KT88s I put in last year before I switched over to the new 6550s. DAMN IT!!!

VPI Classic, Rotel DAC, ARC SP17, ARC VS60, Golden Ear Triton 2s, Nordost and Shunyata. A reasonably decent system that I rarely have time to listen to.
dfwlistener
Try a different tube in the same socket just to make sure nothing was damaged when you installed the new ones.
Good points Jea48. Also did the OP switch the tubes around to make sure that the problem is the tube and not a burned resister.

Btw, there may be an opportunity here. I just checked the ARCDB web site -- News Tab. If you scroll down far enough, the site reports that when ARC cleared KT-120 tubes for use in some of its older 6550 tube amps, the VSI60 was listed. The VS60 was not specifically mentioned. That said, if the innards of the VS60 are the same as the amp part of the innards of the VSI60, going from the 6550 to the KT-120 in the VS60 could make a big improvement.

As an aside, a number of 3rd party tube vendors sell the KT-120 for about $50 a pop. The 6550s might be more expensive depending on the brand. Be careful with so called "original" SED Winged Cs. Many of these SED Winged Cs on the market today are sub par grade. Check out the Upscale Audio web site for the full story.

Dfwlistener ... I sent Kal a message over the weekend about a tube inquiry. Kal's Outlook mailbox sent me an auto response saying that he is on vacation until Wednesday, the 22nd. Try back then.

But please keep in mind my suggestion about switching tubes around to confirm that the problem is the tube and not a burned resister. Also, when you hook up with Kal, ask him if the KT-120 is cleared for the VS60. I do not think you will be disappointed.

FWIW, I used to own the VS-115 which came stock with 6550s. ARC cleared the VS-115 for KT-120s. IMO, it made a dramatic difference for the better.

Cheers,

BIF