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
You should always try out tubes when you get them. Audio Research might just tell you that they are a year old. How would you prove to them that they were never used?
Thanks for the responses guys. I have a compu-bias meter. I didn't change the bias at all from where it was which by the way was on the low side of what the manual recommends. There is no recommendation to reduce bias before tube installation anywhere in the manual. The amp comes from the factory already biased. And yes I did swap sockets and confirm that it was the tube and not a blown resistor. I got a call back yesterday from one of the other ARC guys and he had me send an email to their service department. Th tube was definitely DOA as you can easily see the slow turn on and ramp of the bias current and output power with the comps-bias meter. It didn't arc, pop or any other telltale of failing on installation.

I've been wondering about the use of the KT120s. Thanks for the info BIF. I will definitely inquire with the service guy when we communicate. My local ARC dealer actually suggested the same thing last year. What kind of difference did you hear?
I do agree with Yogiboy. even if you have no intention of using the new tubes anytime soon, you should test them in circuit and see if they work. That way, the company you purchased them from will honor whatever warranty that comes with the tubes. No way can the company tell six months later that you didn't use or abuse the tubes.

In any case, tubes blow. bumping them, dropping them, shipping them, etc. may cause problems. I'm sure AR did as they always do, they tested and matched the tubes before shipping. But @@$$% happens. I'm curious as to why you posted this complaint? Are you upset with the tube? letting it sit for six months before testing it and losing the warranty? upset with AR?

I understand frustration over things breaking, but that is the nature of the beast. Car parts will break. I don't care if it is a Toyota, Nissan, Porsche, etc. Watches break, audio components break. I know people that never maintain their cars, yet complain when they break. They had ample warning to do something, but they are sooo mad when it breaks. As if they were designed to last forever.

Tubes are especially fragile. One of the major reasons why many people want solid state. But oh, with the right tube gear... the sound is wonderful.

I just purchased a pair of AR REF250 amps from my favorite dealer. I've been listening to these amps for two years at my dealer saying that if I ever could really afford them, I would get them.

Well, I did. Took them home, connected them and found one V1 tube blown. What the $$**? Two years of perfect listening at the store on the same amps and take them home and blown tube. Demonstration units. Covered by warranty. Get new tube under warranty and move on.

Best amps I have ever heard.

Had tube amps before. ##$$$ happens.

Sorry for the tube issue you experienced. Not an AR issue. get a new tube, plug it in. Bias it. Listen to great music and move on.

enjoy